Tektronix 494A manuale d’uso

Service Manual 494A & 494AP Tektronix o o o o o o o o o o o I o o o o a o o o o o o o o o o o o o o a o o a o o o o o o o o o Spectrum Analyzers Volume 1 070-ss60-00 Warning The servicing instructions are for use by qualified personnel only. To avoid personal injury, do not perform any servicing unless you are qualified to do so. Refer to the S[...]

Copyright @ Tekrronix, Inc. 1987. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes that in all previously published material. Specifications and price change privileges reserved. Printed in the U.S.A. Tektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070_[...]

o o o o o o o o o o a o I o o O o o o o o o o o o o o O I o o o o o o t o o o o I O a o RELEASE OF COPYRIGHT Tektronix cannot provide manuals for measurement products that are no longer eligible for long term support. Tektronix hereby grants permission and license for others to reproduce and distribute copies of any Tektronix measurement product ma[...]

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I o o I o I t I o o I I O o I t o I I o o o o o o o t o I o o o o o I o O t I O o O t o WARRANTY Tektronix warrants that this product will be free from defects in materials and workmanship fbr a period of one (l) year from the date of shipment. If any such product proves defective during this warranty feriod, Tektronix, at its option, either will r[...]

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o o o t o o I I o a O I a o I I o t I o a o O o I o o o I o o I o o o a o I a o o o o o PREFACE This manual contains servic€ information for the TEKTRONfX 494A1494Ap. The information is tocated in two volumes. Volume 1 contains the text and Volume 2 contains the diagrams and parts lists. The Tabte of Contents in each volume lists the contents of [...]

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TABLE OF CONTENTS The 494A/494AP service Manuat is divided into two volumes. VOLUME 1 Page PREFACE ........................ i TABLE OF CONTENTS .............. .......... iii LIST OF ILLUSTRATTONS ........... ........ x LIST OF TABLES ............. xiii SERVICING SAFETY SUMMARY ......... xv Section 1 GENERAL INFoRMATION product Description .........[...]

o o o I .| r o o a a o I o o t a o O o o o I a o o o t o a a I I I o o o o o I o a a a o tv 49441494AP Servtce Vot. i Section 4 Section 5 TABLE OF CONTENTS (Gonr.) page PERFORMANCE CHECK (Conr.) 24. Check LO Emission .....4-29 25. Check 1 dB Compression point .......4-29 26. Check External Reference Input Power .... 4-31 27. Check Triggering Operat[...]

TABLE OF CONTENTS (Conr.) o o o I O I I o o O I a o o a I o I o o t o o o a o o o I o a a t o O o I o o o a o o o 494A/494AP Service Vot. 1 Section 6 page MAINTENANCE (Conr) Firmware Version and Enor Message Readout ............... 6-1 5 Selected Components .................. 6-1 5 Replacing EPROM or ROM Devices ........ 6-15 Surface-Mounted Compon[...]

TABLE OF CONTENTS (Cont.) Page Section 7 THEORY OF OPERATTON (Cont) DETAILED DESCR|PT|ON ................ ..... 7 -4 1ST CONVERTER SECTTON ............. 7_4 RF Interface Qircuits .................... 7-4 'l st Converter ................. ..........,,,.. 7-4 RF Input ............... 7-4 Preselector Circuits ...........,..... 74 lst Mixer ......[...]

TABLE OF CONTENTS (Conr.) o o o o o o O a o o o a o I t I o I o o I o o a o o o o o t o a I o o t t o a O o o o a 494A1494AP Service Vot. I Page Section 7 THEORY OF OPERATION (Conr) Fast Retrace Blanking ...,.,... 742 Memories ........7-47 DEFLECTION AMPLIFIERS .......... 7-47 Horizontal Section ...............,... 747 Vertical Section ....249 Z.AX[...]

TABLE OF CONTENTS (Cont.) Page Section 7 THEORY OF OPERATTON (Conr) DtctTAL CONTROL SECTTON .......... 7_88 Microcomputer ............................. 7-gg Processor ............. 7-gg Microprocessor ................... 7-88 Cfock ......... ......7-92 Microcomputer Bus ........,.... T-92 Address Decoder ................ Z-92 Timer ......... ......[...]

494A/{94AP Service Vot. 1 TABLE OF CONTENTS (Cont.) VOLUME 2 Sec|ion 9 REPLACEABLE ELECTRICAL PARTS Section 10 DTAGRAMS Section 1.I REPLACEABLE MECHANICAL PARTS[...]

494A/494AP Servlce Vol. 1 Figure page The 494AP Spectrum Analyzer. ................... xvi 2-1 Dimensions. ....,....,..2-12 3-1 Location of input power selector switch and fine fuse. .._....... .....,..,.........9-2 4-1 Crt display at initial power-up. ...................... 4-4 4-2 Typical display of catibrator signal in Max SpanlDiv. ............[...]

LIST OF ILLUSTRATIONS (Conr.) Page Flgure I o o a o I I o o a I a t o I I o t o o I t o a o o a o I I a o o o I o I o a o o o o I 494A/494AP Servtce Vot. 1 Figure 5-21 PreseleetorDriver adjustment setup. ......... ............5_22 5-22 Preselector Driver test point and adjustment locations ........... S_Zg 5-23 Test equipment setup for band levelin[...]

494A/494AP Servlce Vot. 1 o I o a I I o a o I I I o o O t o o o I a I o o I o o o o ) o o a o o I a o I o o o o t LIST OF ILLUSTRATIONS (Cont.) Page Figure Figure 7-12 Selection of disptay position on the log scale. .....7-94 7-13 Functional diagram showing the sp€ctrum analyzer and 1405 TV Sideband Adapter system. ........ 7€6 7-14 Simplified [...]

o a o a o O I I O o o I o I t I I I I I o I o a I o t o I t a o o o a o I o o o o o o o 494A1494AP Service Vot. 1 Table page 1-1 TEKTRON'X WAVEGUIDE MIXERS .............. 1-3 2-1 FREQUENCY RELATED CHARACTERTSTTCS .................. 2-1 2-2 AMPLITUDE RELATED CHARACTERTSTTCS ................. 2_6 2-3 INPUT SIGNAL CHARACTERTSTTCS ................[...]

{944/494AP Service Vot. 1 Table page 8.1 EXTENDED SERVICE AND WARRANW OPT|ONS .............8_1 8.2 OPNON 07 ALTERNATE spEctFtcATloNs ................... 8-2 8.3 OPTIONS 21 AND 22 WAVEGUIDE MtxERS CHARACTERTSTTCS ...................... 8_3 page OPTION 41 ALTERNATE SPECTF|CAT|ONS ......... ............8-4 OPTION 42 ELECTRICAL CHARACTERTSTTCS ........[...]

t o o I o I I I o o o a o O t I o I o I I o o o o I o o o o o o I o o t a o o o o o I I SERVICING SAFETY SUMMARY FOR QUALIFIED SERVICE PERSONNEL ONLY 494A|494AP Service Vot. 1 Do Not Service Alone Do not perform internal service or adjustment of this product unless anoth€r person capable of rendering first aid and resuscitation is present. Do Not[...]

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GENERAL INFORMATION Product Description The 494A and the 494Ap (programmabte) instru_ ments are high performance, compict, portable spec- trum analyzers. Microcomputer control of most func- tions simplifies and enhances operation. The analyzers feature: . single and delta marker modes o synthesizer freguency accuracy o precision signal counting r p[...]

Generaf Infornation - 4g4[l4g4Ap Service, Vol. 1 throughout the United StatEs and in countries wherE our products are sold. Several types of maintenance or repair agreements are available. For example, for a fixed fee, a maintenance agree- ment program provides maintenance and recalibration on a regular basis. Tektronix will remind you when a produ[...]

I o o a o I I o o o o o o o a o a o t I I o o a t o t o I o o o I a o o o I o o o a I o EXAMpLE: R2090 on assembly A2O becomss 420R2090. EXAMpLE: U1044 on subassemblv Al of assembly A36 is found in the ejectrical parts tist as A3641U.t044. Firmware Version and Eror Message Readout This feature of the spectrum analyzer provides readout that identifi[...]

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I o a I o o o t o o o J o o o o I a t a I a o o o o o o I o I o I a o C I o o o o I I o Section 2 - 494A1494Ap Service, Vol. 1 SPECIFICATION This section includes the eiectrical, physical, and environmental characteristics of this insirument. Any instrument specification changes due to options ari listed in the Options section of this manual. ELECT[...]

Table 2.1 (Continued) Characteristic Perf ormance Requirement Supplemental Information I nitial Accuracy (continued) Bands 1& 5-12 with SPAN/DIV (200 kHz, and Bands 2-4 with SpAN/DlV (100 kHz (1st LO locked) t{20%D + (cF x REF) + (2N + 25)Hz) Where: D - SPAN/D|V or RESOLUTTON BANDWIDTH, whichever is greater CF : Center Frequency REF Reference F[...]

Specification - 494Al4g4Ap Service, Vol. 1 - Tabte 2-1 (Continued) FREOUENCY RELATED CHARACTERISTICS tal Inlormation Characteristic Signal Counter (continued) Delta Frequency Accuracy Sensitivity Readout Resolution Ref erence Frequency Error Aging Rate Short Term First six months After the first six months Temperature sensitivity Residual FM 1st LO[...]

Specilication - 494A/494Ap Service, Vot. 1 Table 2-l (Continued) FREQUENCY RELATED CHARACTERTSTICS Characteristic Performance uirement Supplemental Inf ormation cally (-55 dBc (47 Hz - 44A Hz) 3 kHz 300 Hz 30 Hz 3Hz 0.3 Hz Typically 30 psldivision of pulse tude When activated, the marker is a bright dot positioned by the CENTER/MARKER FREQUENCY con[...]

o o O a o o a t o o t o o o o o e o I o I o ? O o o e o o I o o o o o o o o a o o a o o Characteristic Frequency Span/Div (cont) Multiband Mode Maximum Span/Div Band 1 (0-1.8 GHz) Band 2 (1.7-5.5 GHz) Band 3 (3.0-7.1 GHz) Band 4 (5.4-18 GHz) Band 5 (15-21 GHz) Band 6 (18-27 GHz) Band 7 (26-40 GHz) Band 8 (33-60 GHz) Band 9 (50-90 GHz) Band 10 (75-1[...]

Characteristic Performance Requirement Supplemental Inf ormation requency Response Coaxial (direct) Input Band and Freq Range 1 (10 kHz-l.8 GHz) 2 (1.7-5.5 GHz) 3 (3.0-7.1 GHz) 4 (5.a-18 GHz) 5 (15-21 GHz) Measured with 10 dB RF attenuation and peaking optimized for each center frequency setting (when appli- cable) Response is affected by: o input [...]

Characteristic Specification _ 494A1494Ap Service, Vot. 1 AMPLITUDE RELATED CHARAiTERISTICS tal Informalion Top of the graticule. From -117 dBm to +50 dBm; +50 dBm inctudes 20 dB of tF gain reduction (+30 dBm is the maximum safe input). Alternate reference levels arei . dBV (-130 dBV to +97 dBV) o dBrnv (-70 dBmV to +97 dBmV) o dBpV (-10 dBpV to +1[...]

Specification - 494A!494Ap Service, Vol. 1 Characteristic Reference Level (continued) SEt With DATA ENTRY buttons Vertical Display Modes Display Dynamic Range Accuracy 10 dB/div Log Mode 2 dBldiv Log Mode Linear Mode RF Attenuatol Range Accuracy Dc to 1.8 GHz 1.8 GHz to 'l8 GHz 18 GHz to 2'l GHz Marker(s) Accuracy Mode) (Normal or Delta G[...]

o o o I o o o o o o o c I o o o o o a o I o o ) o o o o I o ? o a o O o o I o o a o I o Specification _ 494A1494Ap Service, Vot. 1 Tabte 2-2 (Continued) AMPLITUDE RELATED CHARAiTERISTICS Characteristic lF Gain Range Accuracy 'l dB Step ..-- Decade Transitions Maximum Deviation 107 dB Range Spurious Responses Residual the 3rd Order Intermodulat[...]

Table 2-2 (Continued) Characteristic Perf grmance Requirement Supplemental Intormation Sensitivity Frequency Range Band 1 10 kHz-'t.8 GHz Equivalent Input Noise in dBm vs. Resolution Bandwidth quivalent maximum input noise rr each resolution bandwidth. leasured at 25" C with: . 0 dB attenuation (Min Atten 0 dB) o Narrow Video Filter on . [...]

I o o t o I o I o t I o o I a I o o o o I o o o o O t e t c o o o o o o o I o o o I t 3 Characteristic RF INPUT lmpedance VSWR with 10 dB or more RF Attenuation 10 kHz-2.5 GHz 2.5-6.0 GHz 6.0-18 GHz 18-21 GHz VSWR with 0 dB RF Attenuation 10 kHz-2.5 GHz 2.5-6.0 GHz 6.0-18 GHz 18-21 GHz Maximum Safe Input With 0 dB RF attenuation) 1 dB Compression p[...]

Specification - 494A1494Ap Service, Vol. 1 Characteristic HORIZITBIG (Rear Panel) Sweep Input Voltage Range Trigger Input Voltage Range Minimum Maximum dc + peak ac Pulse Width MARKERIVIDEO (Rear Panet) Video lnput Level Marker Input Level J104 ACCESSORY (Rear Panet) Pin 1 Pin 2 Pin 3 Table 2-3 (Continued) INPUT SIGNAL CHARACTERISTICS Supplemental [...]

Characteristic Speclfication - 494Al4g4Ap Service, Vol. 1 Table 2-3 (Continued) INPUT SIGNAL CHARACTERISTICS Supplemental Inf ormation Internal Control. High (default) selects internal control. lnstrument bus lines are output at the J104 ACCESSORy connector. Low selects External control. lnstru- ment bus lines at the J104 AccES- SORY connector acce[...]

Specification - 494At494Ap Service, Vol. 1 Characteristic EXTERNAL MIXER Bias Range VERT (OUTPUT) (Rear Panet) HORIZ (OUTPUT) (Rear panet) PEN LIFT (Rear Panel) 10 MHz lF (OUTPUT) (Rear Panet) IEEE STD 488 PORT (Rear Panel) Manual version (plotter output) Programmable {P) version PROBE POWER (Rear Panet) Outputs Pin 1 Pin 2 Pin 3 Pin 4 J104 ACCESSO[...]

o o o o t I t o o t o o o t o o o t o o o a o o t o t o o I o o I o o o I o o o I o o I Characteristic Sweep Modes Sweep Time Accuracy Triggering Internal Trigger Level External Trigger Input Level Crt Readout Battery-Powered Memory Battery Life At +55"C ture Ambient Tempera- Tabte 2-5 GENERAL CHARACTERISTICS Table 2-6 POWER REOUIREMENTS Speci[...]

Speclfication - 494A1494AP Service, Vot. 1 Table 2-7 ENVIRONMENTAL CHARACTERISTICS Vibration (operating) (instrument secured to a vibra. tion platform during test) Meets MIL T-28800C, type class 3, style C specifications. Characteristic Descr Temperature Operating and Humidity -15oC to +55oC/95"/" (t 5o/" relative humidity). Non-oper[...]

o I a o , t a o o o ) I o t o I o o o J a a O o o t a o I t o o o o o o o o J o o o o , Characieristic Weight Dimensions (see Figure 2-1) Without Front Cover, Handle, or Feet With Front Cover, Feet, and Handle Handle Folded Back Over the lnstrument Handle Fully Extended Specificaiion - 494A1494Ap Service, Vol. 1 Table 2-8 PHYSICAL CHARACTERISTTCS D[...]

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a O o a o o I I o t I ) I o a I a o o a o o o o o a o o I o o O I o a a o a o o o O o o Section 3 - 494A1494Ap Service, Vot. I INSTALLATION This section describes unpacking, installation, pow€r requirements, storage information and repackag- ing for the spectrurn analy;er. UNPACKING AND INITIAL INSPECT|6N .. Bglorg unpacking the spectrum analyzer[...]

Installation - 494A/494Ap Servlce, Vol. 1 CONNECTING POWER Power Source and power Requirements o a o I a a o o O a o a o I I o o o t o a o o o o O o o o o o O o o a o o o o o o o ) a g-2 Changing the powef input can be dangerous. o Work safely o Know the intended power source o Set the instrument for the power source o Check the fuse for proper rat[...]

o o o o o o o o o o o a o o o o o o o o o o O o a o o o o o a o O o o o o a o o o o o o Long Term - For instrument storage of more than 90 days, retain the shipping container ti iepacXage ttre instrument. The battery in tt e instrume-rit does not require rernoval. package the instrument in a vapor barrier bag with a drying agent and store'in a[...]

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PERFORMANCE CHECK Introduction All performance checks are carried out without removing the instrument covers. The procedures in this section verify that the instru- ment performance satisli€s the performance require- rnents specified under the performance Requirement column in Section 2, Specification. Some parameters and instrument functions tha[...]

Performance Check Procedure - 494A/4g4Ap Service Vol. 1 Table 4-1 EOUIPMENT REOUIRED or Test Flxture Test Oscilloscope Time Mark Generator Frequency Countera Prescaler Function or Sine-Wave Generator Signal Generator Signal Generator Low Loss RF Cable (WL Gore) CrystalDetector Sweep Oscillator Power Meter with Power Sensor 750-to-50(} Minimum Loss [...]

o o o o o o o o o o o o o O o a o o o o o o o o o o o o o o o o o o o o o o o o o o o o Performance check procedure - 4g4br4g4Ap service vor. 1 Table 4-1 (cont) EOUIPMENT REOUIRED Equipment or Test Fixture spectrum Analyzer Tracking Generator 10 dB Step Attenuatora dB step Attenuatora lnterconnect Kita 50O Terminator StepAttenuator- st"pnttenu[...]

Performance Check Procedure - 4g4Ll4g4Ap Servlce Vol. 1 PRELIMINARY PREPARATION o o o o a o o o o o o o o o O o o o o o o o o o o o o o o o o o o o O o o o o o o o o o 4-4 lnitial Power-Up During initial power-up cycle, the instrument type, instrument operating system processor firmware ver_ sion, and the front panel processor firmware versions are[...]

E -28( o a. s r rotx f, -t { { { - -r - - -ta .C DII I I t' I ssqx2 o o o o o o o o o O o o o o a o o o o o o o o o o o o O o o o o o o O a O o o o o O a o Performance Check procedure - 4g4Ll4g4Ap Service Vol. 1 Figure -4-2. Typical display of catibrator signat In Max Span/Div. i Calibrate Position, Center Frequency, Reference Level, and Dynam[...]

Performance Check Procedure - 4g4Ll4g4Ap Servlce Vot. .l PERFORMANCE CHECK PROCEDURE 1. Check 10 MHz Reference Oscillator Accuracy (Aging rate <1 x 10-7) The 10 MHz Reference Oscillator accuracy is not a performance requirement; however, it must be checked so the center frequency accuracy can be verified. Since the calibrator is locked to the 10[...]

o o o o o o a o o a o a o o o I a o o o o I o o o o o O I I o o O o I I o O O o a o o o 4. Check Center Frequency Accuracy . This is a two part procedure; part I checks center frequency accuracy with the 1st LO unlocked, part ll checks accuracy with the l st LO phase lockecl. A front panel CAL should be done before performing this check. Part | - l[...]

Performance Check procedure - 4g4A/4g4Ap Service Vol. 1 TM 5OO Main Frame Flgure 4-3. Test equipment setup for checking center f.equency accuracy. Tabte 4-2 CENTER FREOUENCY ACCURACY CHECK POINTS (1sr LO UNLOCKED) O o o o a o o o o o O o o a a o o o o o o o a o o o o o a o o o o o O o o a a o o o O o Band Approximate Frequency Keypad Entry CENTER F[...]

o o o o o a a I o o o o a o a O a o a a o o o o a o o o O o O o o o o a o o o o o o a o wrTlt F|RST stOilAL ATC€NTER, SEOol{D CAil EE Wrn$t TH|S RAI{OE r| _ta -tt -tl {l -€ € 4' { {l 5s6035 Figure 4-4. Cenler frequency drift with the 1st LO tocked. 5. Check Center Frequency Stabilitv lplrl i.f 50 Hzlmin'or r".J *itii-'irt [...]

Performance Check procedure - 4g4Al4g4Ap Service Vol. 1 cr gl.TttB lm{ iv ra.l ta., t2.a a.l a.a 2-a t.l A C.bubu|g tbp. of |lteon|.. E -2$el .a( t.5:rrq _2rS/--* n la.a ta.t t:.t ra. a,l a.a {.1 2.4 a.l .T IM n B. Lr.r|dog Ft .t lhc drylato||/dl'rlaloo ot urc roapo||ac. Figure 4-5. Typical display for measuriag residual FM. f. lf SAVE A was u[...]

E -Otr .rr t.Eq' i5tr TI -t -- ..4 -r -tt - { -ll ^rla trl 'l ''t I' r' ss603it o o o t O o a o o a o a O o t O a o a a O o o o a o o o a o I o o o o o t t a o o o I o Performance Check procedure - 4g4AJ4g4Ap Servlce Vol. 1 i. Reset the REF LEVEL for tho best marker definirion, and the CENTER FREouENcy t" ariln ii[...]

Perlormance Check procedure _ 4g4A/494Ap Service Vol. 1 8. Check Marker Accuracy Accuracy with the 1st LO untocked is * {(20% of the Span/Div or Resolution Bandwidth, whichever is greater) + (CF x Reference Frequency Enor) * 15N kHzl. Accuracy with 1st LO tocked is * ((20% of the Span/Div or Resolution Bandwidth, whichever is greater).+ (CF x gglsr[...]

o o a o o o a o o I I t o a a o a o o o a I o O o o t o I O t a o a a O O I O o o o o o Performanee Check procedure _ 4g4Al4g4Ap Servlce Vol. 1 SPECTRIfr AI{I.AYZER UI{OER TEST coME OENERATOR MOOULE Figure 4-7' Test equipment setup for checklng frequency span/Dlv and sweep Time/Div accuracy. 9. ^C.*:*_qyegp Time Accuracy (Within S% of the rate[...]

Performance Check procedure - 4g4A/4g4Ap Service Vol. 1 b. Activate PULSE STRETCHER and nore that this mode extends the talt time of the markers. c. Remove the test equipment. o o o o I o ) o o o a a o a o a t o o o o o a o O o o o o a o O a o o O o o a o I o I o Figure 4€. Typlcal display for measuring Time/Div accuracy. 11. Check Resolution Ban[...]

I o o t o t o I o o I I o a a a a O a a o o o o a o o a a I a o I o o o o I O o I o I o Perlormance Check procedure _ 4g4Ll4g4Ap Servlce Vot. 1 g. Check the resolution bandwidths and shape fac_ tors for the 100 kHz (300ftHa for Option bA, 10 kHz, 1 kHz, and 100 Hz fitters. Shape factlistroufd be 7.5:1 or less. h. RESET thE RESOLUTION BANDWIDTH tO &[...]

Performance Check procedure _ 4g4Al4g4Ap Service Vol. 1 14. Check Frequency Response (Response, about the midpoint between two €xtremes, measured with 10 dB of RF attenuation and peaking optimized in the applicabl€ bands for each center frequency setting, is as follows: Band 1: +1.5 dB from 10 kHz to 1.g GHz Band 2: *2.5 dB from 1.7 to S.5 GHz [...]

Perforrnance Check procedure _ 4g4Ll4g4Ap Servlce Vol. 1 4-17 o o o o o a o I o o a o o a a I o I o o o a o o t o J a t t O a I o a o o o o a a o I o Oscillator Sweep Range 3-5.0 GHz 5-7.1 GHz 5.4-7.4 GHz 7.4-9,4 c 70 EXT. ALC III'PUT CO{IINECTOB- F' I o I o RF €XT OUT ALC oo o swEEp oSctLLATOR TO RF OtrT CoxnecG SPECTRUII AilALYZER UND[...]

Performance Check procedure - 4g4A/494Ap Service Vol. 1 ^ b: Check frequency response from 10 kHz to 10 MHz (lower end of Band 1). - (1) Reconnect the_test eguipment as shown in Fig- ure 4.12. Reset CENTER FREQUENCY Io 10 MHz. (2) Set the generator output for _20 dBm at 10 MHz, and set the Spectrum Analyzer controls as follows: CENTER FREQUENCY 10 [...]

t I a o o o o o o o t a o o o a o a a a o a o o a I a o o o o o o o o I t I o O a a I t Performance Check procedure _ 4g4Ll4g4Ap Servlce Vol. 1 (4) Check that amplitude deviation from the 100 MHz reference_does not,*.""J-*i.s dB. Atso check that flatn€ss is within *1.5 dB. c. Connect the CAL.OUT signat to the RF tNpUT, and perform the &[...]

Performance Check procedure - 494A/4g4Ap Service Vol. 1 d. Check that the signal steps down in 10 dB (r1.0 dB) steps as attenuation is added. Maximum cumulative error should not exceed 2.0 dB over the 80 dB range. e. Deactivate the NARROW VTDEO F|LTER, return the external attenuation to 0 dB, and change the VERTI- CAL OISPLAY to 2 dB/DlV. Set the s[...]

t o a o I o o I a a o o a O I I I a O o o o o o a O a o I I o O O o t o o o o I o o a I Cal Factor Test frequency Mode dBm Range Hotd Out .h. setthe signat gen€rator (Hp g3508/s3595A) con- trols as follows: Performance Check procedure - 4g4Al4g4Ap Servlce Vol. 1 Frequency Mode CW Frequency Test Frequency Output Level --5 dBm i. Set the generator [...]

Performance Check procedure _ 4g4Ll4g4Ap Servlce Vol. 1 o o a o o o O o o a o I o o o I o I o o ) I o o I o a o a I I a a o t t a a o a a a o o o. Check that the difference between the SAVE A and V|EW B_disptays is tess than O.S dB up to 1.g GHz, less than 1.5 dB from .t.g GHz to 1g GHz, and tess than 3.0 dB from 18 GHZ to 21 GHz. Make a note of th[...]

o I ) o o o o o a I o o I o t I t a I o o o o o I O o o o I o o t o a t I I a o o t I o Performance Check procedure - 4g4Al4g4Ap Servlce Vol. 1 b. Connect the test eguipment as shown in Figure 4-15. Set the Spectrum Anatyzer controls as followj: l. Establish a reference setting for the first 10 dB increment by pressing dB[Ref on tie po*"i mete[...]

Performance Check procedure - 4g4Al4g4Ap Service Vot. 1 f. Turn off the 50 MHz reference on the power rneter, and disconnect th€ power sensor from the Power Ref Output port. - g. Collect the generator output to the Spectrum Analyzer RF lN through the precision cabte and 10 dB attenuator. h. Set the generator controls for a maximum output power. i[...]

o I a o o o o o o a o I o o I I , o I o I a o o a a a o a o O a I o o t I t o o O a I o .. q: 19.gt the Spectrum Analyzer RF attenuator set- ting to 60 dB, and increase the reference level setting by t0 dB. .r, lheck that t,€ {itEreqce between the SAVE A and. VIEW g.gi.prqfr is ss t"n s.ri o-e. Make a note of th€ levet differe(rce OetNqe[...]

Performance Check procedure - 4g4Al4g4Ap Service Vol. 1 19. Check Gain Variation Between Resolution Bandwidths (Less than *0.4 dB with respect to the 3 MHz fitter and less than 0.8 dB between any two filters) Before performing this check, do a front panel CAL procedure by pressing <Blue-SHIFT> CAL and per_ forming the steps prompted by the sp[...]

o o I o o o o o o a o o o o o o I o I I O a O o o o o o o o a a I o o a I o I a o o o a Performance Check procedurc - 4g4Ll4g4Ap Service Vol. l Table 4-8 SENSITIVITY. tN dBm (dBmV for 75o tNpUT) 21. Gheck Residual Spurious Response With no input signat, -100 dBm oi tessl _a. Remove any signal connected to the RF lNpUT, and terminate the RF tNpUT in[...]

Performance Check procedure - 4g4A/4g4Ap Service Vol. 1 Spactum Analtrar Un(br Totl al|C T{oilt clot Figure 4'16. Test equlpment setup for checking intermoduration distortion. o o t o a o O a o I o I o a o I I a o t o o o o o o o o o o t o o o t I C a a O o o o o freq.-..t, f1 t2 Third (3rd) Order Intermodulation products 2127_.ts Figure 4-17.[...]

o o o o I o s o ) o o o o o I I I t I I I a o o o o o o o t a I a o o a I I o a t a I a 23. Check Harmonic Distortion {-60 dBc or tess frorn 10 kHz to 1.g GHz) {Not discernible above tt " "u"r"g" no]r" ftoor (at teast 100 dBc) from 1.7 GHz to 21-cHti Tested at -90 dBm in MIN DTSTORTTON mode a. Gonnect the test equipmen[...]

Performance Check procedure - 4g4Al4g4Ap Service Vol. 1 Spectrum Analyeer Under Test Figure 4-18. Test equipment setup lor checklng harmonic distortion. d. Monitor the 10 MHz lF output on the rear panel with a test sp€ctrum analyzer through a 1 dB step attenuator. Set this step attenuator for 0 clB of attenua- tion. e. Set the test spectrum analy[...]

o I o o o o o I o e I o o o a o {l I I a I o o a o o e o o I o o o o i o I I o a C o o a l. Check that the 1 dB compression point occurs at -20 dBm or less (20 dB or less attenuation Oetween the generator and the RF INPUT). 26. Check External Reference Input power (+15 dBm to -15 dBm) (1 MHz, 2 MHz, 5 MHz, or 10 MHz.) a. Connect the output of a sig[...]

Performance Check procedure - 4g4A/4g4Ap Service Vol. l Speclnm Andyrcr Undcr Tcst Iodrl.l.d RF Figure 4'20. Test equlpment selup for checking Intemal trlgger characteri3tica. o a o o a o I a o t t e o a o o o a f o t o a o o O o o o a a o o a a o o a o a c o o a 4-32 b. Set the Spectrum Analyzer controls as follows: CENTER FREQUENCY 100 MHz S[...]

a. Connect the test eguiprn€nt as shown in Figure 4-22. Set the Spectrum enityzer "ontroi, "i fouows: VERT|CAL DTSPLAY 2 dB/DtV T|ME/D|V EXT VIEW A and V|EW B Otr b. Set the function generator controls for no output (0 v). c. Use thE POSITION "ontroi to position the crt beam -on the left graticule edge. This'est;btishes the 0 [...]

Performance check Procedure - 4g4Al4g4Ap servrce Vor. I 29. Check VERT OUTPUT Signal (0.5 V *5% per division of disptay from the center line) a. Monitor the VERT OUTPUT with a dc_coupted test oscilloscope. b. S€t the test oscilloscope controls for a sensitivity of 1 V/div and a sweep rate of 10 ms. c. Set the Spectrum Analyzer controls as follows[...]

32.Gheck Option 07 Frequency Response (Response, about . tt"' rniJioini'.0!i*""n two €xtremes, measured with 10 dg oi nF-ettenuation, is *2 dB from S MHz to 1000 MH;i farts.lt-trryugh f check frequency response fro.m t0 MHz to 1 GHz, anO'partJ g il;;;; i;ff;:.t*ouency response from 6 Mllii" Performance Check pro[...]

Performance Check Procedure - 4g4A/4g4Ap Servlce Vol. 1 - c. Set tle_:rlveep oscillator controls for a cw output frequency of 500 MHz and an amptitude of +20 Oe;1V at the 75O INPUT. d. lf necessary, set th€ cAL AMPL adjustment for 5 divisions on the Spectrum Analyzer display. e. Reset the sweep oscillator controls lor a sweep output from 0.01 GHz[...]

33. Check Option 4t Frequency Span/Div Accuracv !1t73 o.t 5 MHz/Div over the cdnter 6 divisions of the display) ., Sp:laccuracy is c_hecked at center frequency set- tings of 6 GHz and 11 GHz. a. 'Connect the test equipment as shown in Figure 4-26. set the sp€ctrum Analyzer "ontroir ", follows: Perforrnance Check procedure - 4g4ful4[...]

Performance Check procedure - 4g4Al4g4Ap Service Vol. 1 34. Check Option 42110 MHz OUT Level ((0 dBm for Band 1) (>.-40 dBm for Band 5) . a. Tune the Spectrum Analyzer CENTER FRE_ QUENCY to 100 MHz. b. Connect a signal generator to the RF lNpUT. Set the signal generator output frequency to i00 MHz, and output level to -30 dBm. c. Set th€ REF L[...]

o I o C o t o t o o I ) t I C o a o o c o o t a o o o o o o a o a o o o c O o o a o I o 7L14 Center Frequency Freq Span/Div Hz Resolution Reference Level Display Mode Digitaf Storage TimelDiv Triggering Source Mode Video Filter 110 MHz 1 MHz 3 MHZ 0 dBm 2 dBlDiv off Manuaf Free Run Norm On Performance Check procedure - 4g4Al4g4Ap Service Vol. 1 j. [...]

Performance Check procedure - 4g4A/4g4Ap Service Vol. I Lines 9000-10000: Group Execute Trigger test. Checks that a GET message does cause the Spectrum Analyzer to abort the present sweep and re-arm the trigger, causing a sweep to start and end, sending out an End-of-Sweep SRe. Thus, the SRe line and GET m€ssage are verified. Lines 10000-11000: S[...]

o o o o a o t t o o o o t a I I o o o o o o t I a o t o I o o o o a o a o r C o o o I o Performance check procedure - 4g4A/4g4Ap service vor. 1 5130 A1-vALrr$) 5140 tF A1>0 AND A1 <31 THEN 5180 :1i9lllltl "{JJGERROR!! ';A1;, tS Nor A vALtD ADDRESS,,; 5160 PRINT " ONLY O THRU gO INE VALID ADDRESSESKK' s170 co To 5080 5180 P[...]

Performance Check procedure - 4g4Ll4g4Ap Service Vol. 1 8060 PRINT @A1:'TlM?, 8070INPUT @41:T6 8080 tF R<>T6 THEN 8100 8090 GO TO 9000 8100 PRINT "J".. GO TO LOCAL...........GTL '* FAIL *rG, 8110 cO TO 19530 8120 REM 8130 REM 8140 REM 8150 REM 8160 REM 9OOO REM "' GROUP EXECUTE TRIGGER........GET'*' 9O1[...]

t O o I o o ? o o c o o I ) o T o t o a o o o o o e a o o o o e o o ) t o o a o o I a I perrormance check procedure - 4g4A/4g4Ap servrce vor. 1 11120 REM 11130 REM 1 I 140 REM 12OOO REM " ADDRESSED AS LISTENER, TALKER "' 1 201 0 pRtNT,... 49xp ADDRESSEb- ndlisreneR...*tr I ?9?9 I/-BvTE @32+Al : 76.zg,se,6s,id,-eJ 12030 T6-1 12040 cos[...]

Performance Check procedure _ 4g4Ll4g4Ap Service Vol. 1 14190 PAGE 14200 A1-16 14210 GOSUB 19000 14220PR|NT" 0 L0l0 l_1o0oo. 14230 GOSUB 19070 14240 GOSUB 19190 14250 REM 14260 REM 14270 REM 14280 REM 14290 REM 15000 REM ., nLFr oR ,EOl. swlTcH .," 15010 PAGE 15020 41:1 15030 cosuB 19000 15040PR|NT. 0 to L 1 !_0OOO1" 1s050 GosuB 1907[...]

I o o C o a I I o e C o o a o ; o I a o o a o o o e o O t o o C o o o o o o o o a ) o o performance check procedure - 4g4Ar4g4Ap servrce vor. 1 17120 PR|NT' 0L ol_ 0LO OOO I, 17130 cosuB 19d70 1 7140 PRTNT @A1 :'REF?,, 17150INPUT @At:V$ 17160 tF v$<>"REFLVL +0.0. THEN 17180 17170 co To 18000 11199lltu IJ{L|SrEN ONLY MODE '[...]

Performance Check procedure _ 4g4Ll4g4Ap Servlce Vot. 1 19260 RETURN 19270 REM 19280 REM ". SRQ HANDLER ". 19290 T6-3 19300 cosuB 19390 19310 POLL 21,21;A1 19320 PRINT @A1:"ERR?" 19330INPUT @A1:S$ 19919 !l!NT "GGAN TNTERRUPT occuRRED oN rHE BUs, rHE 4exp RETURNS ";s$ 19350 pRtNT "JPRESS RETURN <CR> TO CONTTN[...]

ADJUSTMENT fntroduction l{ the lnstrument performance is not within specified requarements for a particular characteristic, determine the cause, repair if necessary, then use the appropriate adiustment procedure to retuln the instrument operation to .performance specification. After any adjustment, verify performance by repeating that part;f the pe[...]

Adluctment Procedure - 4g4A/4g4Ap Servtce Vot. 1 o o o o o o o ) o o o o o o ; a o o I I o O o o t o o O o o a o ) o o o t o I o a a a o Table 5-l EOUIPMENT REOUIRED Equlpment or Test Flxture lsolation Transformer Att€nuator (3 dB miniature) Autotransformer Multimeter Dc Block Adapt€r (Sealectro male to male) Adapter (bnc female to Sealectro ma[...]

o o o o o o o o o o o a o o o o o O o o o o o o o o , o o o a o o o a o O o o o o o o o 1. !{iust Low Vottage power Suppty (R6028 and R6061 on the power Su'pljly board) This high-efficiency power supply uses an internal oscillator with a frequency of 66 i<fiz. The frequency adjustment is normally -required only after replacin! oscillator co[...]

o o o o o o o o o o o o o o o o o o o o o O O o o o o o o o o O o o o o o o o o o O o o Adjustment Procedure - 494A/494Ap Service Vol. 1 F1035 F1033 R6028 {+15 V adjurt} is acceccibte throogfr screw hole Rfl)6l TP6O53 €tr8 Figure 5-1- Low voltage power supply adiustments.[...]

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 2. ^qlult Z-Axis and High Votrage Circuits {110?1, R1027, Rlogo,-R1ost, tno-ili0s8 on the Z-Axis board; R2O4A and R3030 on the High Vottage board) a. Switch POWER off and preset the foilowing Spectrum Anatyzer controls: Adjustment Procedure - 494A/494Ap Service [...]

AdJustmant Procedure - 494A/4g4Ap Service Vot. .l Figure 5-3. Adiustment and test point locations on Hlgh Voltage module. (3) Switch POWER back on. After the instrument initializes, activate 2 dB/Dtv and switch Digital Storage off. (4) Adjust Intensity Limit R1027 (Figure 5-2) for a voltage reading of 0.9 V at Tp402B. (5) Switch POWER off and re-in[...]

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o O o o o o o o o o o Figure 5-4. Test equlpment setup for adiusting the D€flection Amplifier. Adiustment Procedure - 4g4Al4g4Ap Service Vol. 1 p. Adjust C4061 for the best response. Figure 5-5. Test points on the CRT Readout board. i. Disconnect the voltmeter, set TIME/DIV to AUTO[...]

Adfustment Procedure - 4g4Ll4g4Ap Servtce Vot. 1 Flgure 5€. Deflection Amptilier test points and adiuetments. o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o O o o o o o o o o o o o q. Monitor the collectors of e1095 and e20g6, on the Deflection Amplifier board, with test oscilloscope. r. Adjust C5104 tor best response. s, Disconn[...]

o o o o o o o o o o o o o o o O o o o o o o o o o o o o o o o o o o o o o o o o o o o o AdJustment Procedure - 494A1494Ap Service Vot. 1 lnput Gain,RlO3a O.rtput Of*t ouFur Garn R1033 | nrors iITAL STORAGE HORIZONTAL RIINC G.io R1OOo Figure 5-7. Digltal storage adiustment locations. TO: TTARKEBiVID8O TITE TIARK GEI{ERATOR ffi Itull =z BETWEEI{PINS[...]

Adjustnent Procedure - 4g4A/4g4Ap Servtce Vot. 1 Figure 5-9. Sweep board tlming adiustment and test point locations. o o o a o O o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o The Spectrum Analyzer has a procedure in firmware for calibrating the frequency control system. However, it is possible that some adjustments may[...]

a o o o a o o o o O a o o a o o O o o o o o o o o o o o o o o o o o O o o o o o a o o '' 7. Adjust Log Amptitier (R1012, R102S, R1030, R1037, and R.t060 on the Log Amptifier board) Use only an insulated screwdriver or tuning tool to make these adjustments. . a. Set the Log Amplifier correction factors to zero b_y pressing (Bfue-SHtFT> [...]

o o o I a o o o o o a o o o o o o o o o o o o o O o a o o o o o o o o o O o o o a o o (?, 5565-19 Analyzer Under Tesl &21 Ampl Bd BilC fo Sorlos:tro Ad.gtCr 'lO dB Stcp Attcnu.tor 1 dB Stcp An nu.to. m LHr Lcvclod Signrl Gcocr.to?,0-lO dBm To on Log Spectrum @"o.@"@"G)Pt I I 1 Figure 5-12. Test equlpment setup for adjusting [...]

o o O o I I o I o o o t o o o o o I o o o o o o o o o o a o o o o o o o a o o o a o o O .- .k. lctlvate 2 dB/Dtv and add 10 dB of artenuation. lf..the 1098 step (S division) is short, adjust the gain slightly with R'|037 in the same direction;'then rem-ove the 10 dB of external attenuation and adjust R1012 for a full.screen display. Repea[...]

Adjustment Procedure - 494[l4g4Ap Service Vot. 1 Figurc 5-14. Test equipment 3etup tor adiusting tlre Varlable Re3olution rnoOut". 5[ton'"*' ffi I Filrc. sotocr I 6097-18 , o o a o o o a o o a o o o o o o o o o o o o o o o o o I O o o o o O o a o O o o o o a v. Check LIN disptay linearity by adding 6 dB, 12 dB. and 18 dB of atte[...]

o o o o o o t t o I o O o O o o o a o o o o o a a o O o o a o O o O o o O o a o o o o o Flgure 5'15. Adiu3tmonts on the rear of tre Variabre Resorudon modure. (3) Connect the output of the Variable Resolution module to the input. of lhe Log Amplifier assembly by connecting a cable from J6g2 on the Variable Resolution Module to J621 on th€ Lo[...]

Adlustnent Procedure - 494ful4g4Ap Servtce Vot. 1 Flgure 5-16. 100 kHz over l0 kHz litter respona€. (1) Set the, foltowing adjustments to midrange: R4025 on the VR 2nd Fitter Select board, and R3OIO 'and R3025 in the 10Hz/100H2 Bandpass Fitter assembly. (2) Install jumpers on J30i5, JgogS, and J3052 in the 10 Hzll00 Hz Fitter assembty (Figur[...]

o o o a O o o I O o I a o a o I o I O o o a o o o o a o t I o O O o o o o t a o o o o o (29) Press RECALL SETTTNGS 2. !30) Adjust C4060. in the 10 Hzl100 Hz Bandpass Filter assembly for best symmetry. lgtt Repeat parts 2g through 31 to etiminate interaction. (32) Remove ail jumpers from the 10 Hzl100 Hz Bandpass Filter assembly. (33) press <Btue[...]

o O o og o o $o o3 $o oE EooE a $o go0F go o o , oH o o o Adiustment Procedure - 494A1494Ap Service Vol. 1 Figure 5-18. Adiustments on the 10 Hzl100 Hz Bandpass Filter assembly. FILTER Filter Locatlon Preset the Variable Resolution Gain and Band Leveling (R1030 on the Post VR Amplifier board) (R2031 on the Va #2 Mother board). (R3035 on the 10 dB G[...]

b, - O O o I o I o I o I O o o I o t o o o o o o o o o o I O a a o o o o I o o o o o o o Adjurtment Procedure - 494A1494Ap SeMce Vot. I e. Disconnect p693 (Figure 5-17) and activate MtN NOISE. Apply a 10 MH4 -25 dBm signat, from the sig- nal generator, through a bnc-to-sealsctro adapter to J693: Set the genorator frequency to peak the signal amplit[...]

Adiustment Procedure - 494A/4g4Ap Service Vot. 1 10. Adjusf Calibrator Output Level (R1041 on the 100 MHz Osc and 3rd Converter board) The calibrator output level is matched to a known reference. A power meter is used to verify the output level of the reference sig_ nal generator. Harmonics of th€ signal gen_ erator must be greater than 40 dB dow[...]

o o o a o o O I o a I a a o t t t I o o O o o o o o a o I o o o I o o o o I I o o t I a Adjustment procedure - 4g4Al4g4Ap seMce vot. 1 Figure 5-20- lF gain test setup, and adjustnent and conn€ctor rocason3- 12. Adjust B-SAVE A Reference Level (S1015 on the Verticat Digitat Storage board) when B-sAVE A is selected, the expression imple- mented is [...]

Adlustment Procedure - 494A/494Ap Servlce Vot. 1 Figure 5-21. Preselector Driver adiustment lietup. o a o o o o o I o o I a a a I o o ) o a o o a O o o o o t o o a O O O o o o o o I o o o b. Set th€ test equipment as follows: Time Mark Generator .l 0 ns Comb Generator On c. Connect the DVM between the center tap of the MANUAL PEAK potentiometer a[...]

o I o o O O o I o O o I a a o o t a a o o o o o a o a O I o a o I a o o I t o o a I a a o { A Adrustment Procedure - 4g4A/494Ap Service Vol. l $tsr. h - 1,",1 ';'i 1'[ -''l Figurc 5-22. Preselector Driver test point and adiustment locations. . m. Repeat parts k and I to compensate for int€rac_ tion. n. lncrease FR[...]

Adfustrnent Procedure - 4g4A/4g4Ap Servtce Vol. 1 o I o a o o o t o a I t O O o o a t o a a o a O a o o o O o a o t o o o I o o o o o o o Figure 5-23. Test equipment setup for band leveling adiustmenl 1tt. Adjust Band Leveting lor Coaxial Bands (Bands 1-5) (R2031, R3034, R3090, R9019 and R3022 on the VR #2 Mother board) The mean value of the freque[...]

a I o o o o o I o o o t o t o I I I o a a o o o o o t o o O a o o a o o I t o o a o o o . f. Adjust Band 2 Gain RgOg4 on th€ vR Mother b.oard #2 (Figure 5-241 tor a fult screEn (_20 OBml display. _ g. Chang€ th€ FREQUENCY RANGE to 3.0_ 7.1 GH.z (Band 3) and appty a catibrated _20 dBm sig- nal with the same frequency as noted for the mean leve[...]

AdJustnent Procedure - 494A/4g4Ap Servtce Vot. I To: Vsrt liignel Out (back penell Spectnrm Analyrer Under Tegt Flgure 5-25. Test equlpm€nt retup for adjusting llre phase Lock assembly. o a o o o o o , a a o I a I o a t I o o o I a a o a o o o o o a t O o o o o o o o o o O (3) Connect the counter to the coll€ctor of e1040 and not6 the frequency[...]

0@ coitrnou.ED OSCIIIATOR PSI B o c1013 c,rll @@r o*tto @ (E J-ffi] @ @ snrnasrzen @ l-r rP2C3 E rpzoro El TP10'|O @ Cf 0 put.l El Ptilt- L-J @ oFFsE nrxEn @ A Syntfredror, Oftrrt l|h.r, rnd Gontlotocl Orcileor. LOOPOA0T R30!2 n TP36T E TP,OI5 EI | "trrl c2105 o fTr.t I STROBE DRIVER Ft 004 B. Stiobc Orlyrr rnd Eror Ampllllcr. Adrustment [...]

Adiustment Procedure - 494A/tg4Ap Service Vol. 1 (3) Connect the counter to Tp2o11 on th€ con- trolled Oscillator board (Figure 5-26a) and atter- nately press AUTO RESOLN and IDENT and check for a count reading of either 25.0g4g MHz or 25.0328 MHz. f. Chec-k Opera0on of Strobe Drlver The *Phase Lock Synthesiz€r" test is still used for this[...]

o o o o o I o a O I a a o t o I I I I o a t a O t o o o t a o a I a o a I a o o o o o I 07) Move p2035 back to pins 1 and 2, reptace P3057, and disconnect the iest oscilloscope from the Error Amplifier board. (18) Reduce SPAN/D|V to 200 kHz and ensure that phase lock occurs, by the absence of error rnessage and a sweep. Replace the covers on the as[...]

DC503A I [[ ORF oo lc ba 1* RF OurO LO lst LO Input rrn I e RF ln I O lrtlO O P1024 P1012 P1010 (rF ouT) (OUr) (tN) H:N Adrustment Procedure - 4g4A/4g4Ap Servlce Vot, I o o o o o t I t O t o a t t o a o o o o I t a a I o o o a O a a o a o a o o o o o o o o Figure 5-27. Opton 42 adiustment test equipment setup. c. set the 7L14 Time/Div to Manual, an[...]

a o o o a t o o o o I t o I o I a o I t o a o o o O o o a o o O t a o o O O I O o o I I Sectfon 6 - 494A/494Ap Servicc Vot. 1 4. Nothing capabl€ of generating or hotding a static charge should be allowed on the work station sur- face. 5.. Keep the cornponent leads shortEd together whenever possible. 9 Pick up components by the body, never by the [...]

PREVENTIVE MAINTENANCE Preventive maintenance consists of cleaning, visual inspection, performance check, and if needed a recali- bration. The preventive maintenance schedule that is established for the instrument should be based on the environment in which the instrument is operated and the amount of use. Under av€rage conditions (laboratory sit[...]

o a a o o I o o o a o ) t o t o I a t a o e a a t o t o o o t o o o I o I o o o o o I o Maintenance - 494A1494Ap Service Vol. 1 Table 6-2 SERVICE KITS AND TOOLS Nomenclature Service Kit consisting of: 'l Front panel extender 1 Power module extender I Accessories Interface extender 1 Ribbon cabte 3 Coaxial cables, Sealectro male-to-S€atectro [...]

Malntenance - tl94A/494Ap SeMce Vot. 1 Schematic diagrams list the Tektronix part No. (670-xxxx-) for the assembty or board atong with the assembly number (e.9. AS0) and name. The tast two digits or sufftx of the part number are not indicated on the diagram, however, they are list€d in the El€ctrical Parts section. These two digits rsflect chan[...]

Diagnostic Firmware The firmware in the sp€ctrum analyzer provldes diagnostic routines that can be used wittr itre Diagnostic part of this section to troubl€shoot th€ Frequency Con- trol system and diagnose power Supply problems. This part fottows GenErat trouOtestrbttini information. Refer to this part to help isolate probljms within this !9[...]

Malntenance - 4tt0[l4g4Ap Servlce Vol. I Because the frequency control loop may be unlocked when using the internal reference freguency in a ucold' instrument. no error messag€ is displayed for the internal refer- ence unlocked condition. How€ver, l_U (lnternat-Untock) is disptayed at the REFER- ENCE OSCTLLATOR positaon for the normal inst[...]

o o o o o o o o o o o a o o o o o o a o o o o I o o o o o I o o o a o I a o | o o a o o (1) Press <Btue-SHtFT> PULSE STRETCHEB and #0, then setect either the lst to reaoout lmenu item #1) or the lnd fg.readout (menu iteni *e1. I!9 _LO frequency wiil be displayect on the crt CENTER FREQUENCY readout pbsition. (2[fter n-oting the.freque^ncy of [...]

Malntenance - 494A/494Ap Servlce Vol. 1 f. lf the fuse does not open and the vottage is still absent, it indicates the trouble is the power Supply. (E) g. lf the voltage from a current limited supply is absent or low, the problem could be the supply, or cir- cuits the supply furnishes may be drawing excessive curr€nt. Turn the POWER ofr, then dis[...]

Mafntenance - 4g4ful4g4Ap Servtce Vot. 1 1ST LO CONTROL DIAGNOSTIC AID NOMINAL -6.79 V 3.43 V DESIRED 2.720 504 c|-1.z 45.896 MHZ DAC TUNE VOLTS SENSE VOLTS lST LO FREQ MIXER FREO 1ST LO SETNNG ACCURACY AUXILIARY SYNTHESIZER PRESS 'SH|FT" TO EXIT -6.80 V 3.43 V 2.719 735 cHZ 46.665 MHZ 4.981 MHZ 212.800 MHZ The Desired l st LO Freq is th?[...]

Mafntenance - 494A1494Ap Servtce Vot. 1 a. lf the calculated and measured frequencies are within 50 MHz of each other and the mbasured fre_ quency agrees with the internally count€d 1st LO Freg readout or differs from it by a multiple of the Auxiliary Synthesizer Freq, r€turn to normal opera_ tion- (by pressing <Btue-SHtFT>). Now attempt [...]

(b) lf the -e1o-r-9cnr: with frequency spans greater than 5 MHz/div, ttre t si t-O is iroO- abty defective. (E) (4) lf the measured and calculated currents are not equal, th€ problem is likely in the final stage of the LO Driver. (E) 4. Measure the lst LO tuning voltage at edge con- nector 47, of the Center Frequeniy Conirot boarO. Ttris voltage [...]

Malntenance - 494A1494Ap Servtce Vol. 1 5. Measure the 2nd LO Tune Volts at Tp1044 on the Center Frequency Control board. a. lf the 2nd LO tuning vottage is within 200 mV of the DAC SEt value, measure the 2nd LO frequency at the front-panet 2ND LO Output connector. (1) lf the measured frequency does not agree with the internally counted roadout. th[...]

a o I o ) o t o o I o ) a o o |, a o t o a o o I t o I o o o a a I o o O o e o o a o e I a. lf.b€at notes are present, press HELP to enable the lock. Check the- Error' Amplifiei output at T?2O3T, on th€ Error Amplifier OolrJln the prrase Lock module. gutput signat amptituOe'sfroufO Oe approximately 6 V peak-peak aho its frequency shou[...]

Malntenance - 4S4Al4g4Ap Servtce Vol. 1 o a o o a a I o o t o t a o o o t o t o o o o a o a t o o o a a a o o o o I t o o I o a TRACE MODES Trace Mode provides information on how the fre- quency control system is working. lt is acc€ssed by pressing <Blue-SHtFT> PULSE STRETCHER. menu item #7, then selecting lst LO (menu item #1),2nd LO (menu[...]

CORRECTIVE MAINTENANCE o o o o o o I o o o ) ) I t o t I o C o t o o o t o o o o o o o t o a o o C o o J o I o Maintenance - 494Al4g4fup Service Vof. 1 Corrective maintenance consists of component replacement and instrument repair. Speciat tecnhiques and procedures that may be iequirJj to-remove and replace assomblies and/br "ompon"nis in[...]

Malntenance - 494A1494Ap Service Vot. 1 o o o o o o ) o o o o I o t I a a o o o f o a a t o o o ) o I o a o o o o I o o t a t o Table 6-4 SELECTED COMPONENTS t Number 422A1Rl070 422A1R2049 422A1R2070 422A1R2072 A46A1R1011 1Rl012 446A1Rl013 446A1 Rl014 A46A1 Rl015 446A1Rl010 1R1020 446A1Rl048 Rl049 446A1R1050 1Rl A46A1Rl052 A46A1Rl053 A46A1Rl055 450[...]

o o 3 o o o o o o o o ) I I o I a I o o I o o o o o o o o o a o o o o o o t o o a a o o Mafntenance - 494[l4g4Ap Servtce Vot. 1 SERvIcING TooLs FoR BoARD'Tffi3.i*,o"= MouNTED coMPoNENTs Replacing Surface-Mounted Components A Hot Air Machine, such as Hart Model 200A manufactured by Nu-Concept Computer Systems lncor_ porated of Colmar, penn[...]

ct66.t-14 Figure 6-2. Diode polartty marklngs. Maintenance - 494A/494Ap Servtce Vot. 1 Diode Color Code The cathode of each glass encased diode is indi- gated by a stripe, a series of stripes, or a dot. Some diodes have a diode symbol printed on one side. Figure 6-2 illustrates diode types Lnd potarity markings'that are used in this instrument[...]

o a a o o o o o o o o a o o o t O I o o e a o o o c o o I o o a o o a o a o o O o O o o lf you desire to remove the component l€ads, use a J.5 Y ol tess pencil type iron. Straigtrten-the teads on me oacK side of the board; then when the sotder melts, gently puil the sotdered tead through the hote. A desoldering tool should be used to -remove the [...]

o a o o a o o o o o o o o c o o o o o o ) o o o o c o o o o a O o o o I o o o o O o o o A30-POWER St,PPLY A30A57-GPIB INTERFACE A62-LOG & VIOEO ATPL A61_DIGITAL STORAGE YERT A6O-DIGITAL STORAGE }IORIZ As8-PROCESSOR 456_GPIB A5'-MEMORY A26_AUXILARY SYNTHESIZER A51_COUNTER A/f0-SPAN ATTENUATOR A/16-CENTER FREO COilTROL PHASE LOCK SYNTI{ESIZE[...]

O o o o o o o o o o o o a o o o o o o o a O o O o o o o o a a o a o a a o o o o o o o I Maintenance - 494Al4g4Ap Service Vot. 1 FL36 FL15 A32-110 ilHr IF AMPL 413_POWER OIVIDER A23-E29 trtHz 2ND CO}IVERTER AlE- 2072 MH: 2ND CONVERTOR 434-3RD CONVERTER A2{-PHASE GATE FL12_ PRESELECTOR FL'O & A1O LIMITER s11 sl2 FL'1 A1'-DIPLEXER A[...]

Mafntenance - 494A1494Ap Service Vot. 1 Some circuit boards and assemblies must be placed on extenders to access test points or adjustments. Before removing these boards and assembli6s, the air bafie attached to the left siderail must also be r€moved. Turn the power off before removing an assembly. Removing and Installing the GplB Board The GPIB [...]

o o o o o o o o o o o o o o o o o o o o o o a o o o o o o o o o o o o o o o o o o o o o 5. Open the diode package. Use a pair of tweezers to grasp th€ diode assembly by its side, and place it on a static-free surface. Grasp t-he side of the'"rr"rOty with^the fingers. Avoid coniact with the diodes. Insert the 8-32 screw. 6, Orient t[...]

Maintenance - 4g4A/4g4Ap Seruice Vot. 1 - 3. Unplug the CAL OUT coaxial cabte from the grd Converter; then disconnect the five crt cables from the Z-Axis/RF Interface, High Voltage module, and Deflection Amplifier. 4. Looking at the top of the instrument, remove the one screw that holds th€ front panel to the side extru_ sion between the crt and [...]

o o o O a o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 7. Reinstall p361. mounting bracket then ptug pg045 onto th€ power supply board anO repacJ the cover. 8. Set the instrument with the RF deck on the near side. then hold the power supply module at the rear of the instrument so the right side is touctring the si[...]

Fan brackets should be installed as in Fig- ure 6-8. 7. Insert the posts of the brackets into the holes provided in the resilient mount and install the remaining bracket, with lockwashers and nuts, to the back side of the power supply housing. 8. Reconnect the fan to the Fan Drive board then replace the cover, with the fan, onto the power supply mo[...]

o o o o o o o o o o o o o o a o o o o o o o o o o o o o o o o o o o o o o O o o o a o o Four Cavlty Fllter-The characteristics of the filter are checked with a network analyzer. Freguency of the filter is 2A72MHz, bandpass, t-S Ul-lz down, is 1 dB, return loss is 20 dB or greater, and insertion loss is 1 clB. lf the seal is broken on any tuning slu[...]

Mafntenance - 494A1494Ap Servtce Vot. 1 Input c1045 c2047 Flgure 6-10. 110 MHz lF test poinb and adiuetmenb. 110 MHz Three Cavity Filter Alignment of this filter is not required unless the spectrum analyzer fails to meet bandwidth specifications. The filters are adiust€d for center fre- quency and response shape so the resolution bandwidth is wit[...]

o a o o t o t o o I o a o t a O a o o o a a o o o o O o o o o o o o o o o o o o o a o o 829 MHz Converler Maintenance Some circuit boards in this assembly contain critical-length printed elements. When damaged, these elements are usually not repairable; therefore, the cir_ cuit board must be replaced. even itroujfr repfacement bgards .are precalibr[...]

Maintenance - 494A1494Ap Service Vot. 1 _ Check the freguency by noting the reading on the frequency counter. lf above 729.900 MHz, the stub must be lengthened. Solder a bridge across the cut "q r.e"!99 frequency. Nominal frequency for an uncut stub is 710 MHz. f. Shorten the line so the frequency is near 723.500 MHz. For example: The fr[...]

o o o o o o I o o O o a O a t o a o o a O o a o a o t o a O I o I o o o o o o o o a o o g. .With the adjacent resonator (second) shorted to ground, adjust the series capacitance by benOing tne tab so the response on the_spectrum analyzer display is centered at 829 MHz (see Figure 6_16A). - h. Now move the shorting strap (screwdriver) to the next re[...]

Malntenance - 494A/4g4Ap Service Vol. 1 Flgure 6-'15. 829 MH: Converbr lilte. hlne tabs. Troubleshooting and Calibrating the 2nd LO The 2182 MHz Oscillator and 2200 MHz Reference Mixer contain critical printed elements that are difficult to repair. Therefore the board should be replaced if damaged. lf the oscillator frequency is beyond adjust_[...]

o O o I a o o I O o o t o I o I I I o o O o a O o O a O o o a o o o O o o o o o o a o o Malntenance - 4g4A/4g4Ap service vot. 1 A 3rd Resonator Retu?n Lo-ss >12 dA B. 4th Resonator and Fllter Figure 6-17. Corect re3ponse tor g29 MHr tlrlrd and fourth resonators. d. Set the Time Mark generator for 0.1 Fs markers. Markers should appear on the test[...]

o o o a o o o o o o o o O o o o I o o o o o o o o o o o o o O o o o o o o o o o o a o o Maintenance - 494A/494Ap Servlce Vol. 1 Table 6-7 EQUIPMENT REOUIRED FOR 2nd LO CALTBRATTON Test Equipment Characteristics Recommended Type Spectrum Analyzer Frequency range to 2.2 GHz TEKTRONIX 49X-Series or 7L'14 Option 39 UHF Gomb Generator 500 MHz Pulse[...]

o o o a I o o I O o o O O o I o a I a a o o a o o I o O I o a O I o a a o o O o o o o o Preparing the 2nd LO Assembly lor Adjustment .. T_":! _"guipment setup is shown in Figure 6-19. Turn the POWER off. Rernove the cabinet and place the Spectrum Analyzer_upside Oown io-ine nf Oect< is exposed. Use a 5/16 inch wrench to loosen and remo[...]

Maintenance - 494A/4g4Ap Servtce Vot. 1 2lE2 }'/Hz tro||! Unbuttcrcd OrIput Porf ffiffi o@@@ @ 9o Flgure 5-19. 2182 MHz Phase Locked 2nd LO adiustment letup.[...]

t o a I o o o o o a o a o a o o I I o o I a a o o o I o o t a t I a I t o o o I o o t I Maintenance - 4g4Al494Ap Service Vot. 1 c2201 TP +12 V ol ?o,il,- .e: ,- zrfP2o3s-+o 5 r (2)-- r _rr r1l*rffi Figure 6'20. 16-20 MHz phase Lock circuit test point and component rocadons. H222 21E2 tH: Bullercd Output port 2182 llHz MGrorlrip Olcitfatof ?zm [...]

Mafnfenance - 4g4Ll494Ap Servtce Vot. 1 Figure 6-22. Coaxial test probe construction detaits. 3. Gheck the 2200 MHz Relerence Mixer a. Use a probe, consisting of a short length of semi-rigid coaxial cabte with a dc block (see Figure 6_ 22), to connect the output of the reference mixer at Q2204-to the input of the test spectrum analyzer. Ground the [...]

6-39 o O o a O o O t o I o I o I I t o I a a o a a o o a o o I I a a I O o a o o a o a o o I Maintenance _ 494A/494Ap Service Vot. 1 Tabte 6-g EOUIPMET.IT REOUTRED FOR CALTBRATING THE 16-20]VtHz pHASE LOCK C|RCU|T Tesl fqulprng6l Characteristlcs Recommended Type utgtrat v9tlmeter Frequency Counter Time-Mark Generator Measures to within 0.Ol V, impe[...]

Maintenance - 494A/{g4Ap Servtce Vol. I Troubleshooting and Galibrating the 16-20 MHz Phase Lock Section Replacing oscillator components in this section may alter sweep linearity and the oscillator frequency. Thi following checks and calibration aid in repairing and retuning the assembly. 1. Preliminary _ a. Test equipment setup is shown in Figure [...]

o o o a o o o o o o o o o o I o o o a a o a o o I o a a I I I a I o o a t o o o o a o o Maintenanco - 4g4A/4g4Ap Servlce Vol. 1 Figure 6-24, Tune and Sweep Range adjustnents. R404O Fine Tune Ranee -+! CENTER F REOUE'{CY COI{TROL A. Location of R4040, Fine tune Renge. ) B. Location ot R|O6Z.2nd LO Sweep.[...]

Maintenance - 494A/4g4Ap Servlce Vot. 1 5. Setting Sweep Range a. Apply 5 ps time markers from the Time Mark Generator to the RF tNpUT. Set the FREO SPAN/D|V to 500 kHz then back to 200 kHz to center the 2nd LO frequency. b. Adjust the REF LEVEL to disptay the 200 kHz markers then center one of the markers with the CENTER FREOUENCY controt. c. Adju[...]

o o o o o o o I o o o o o I I I I o a o t a o o o o o a o I I o I o o O o I a o o a o o _ ^ wIT the foop is unlocked, RF teakage from the 16-20 MHz osciilator buffer is present .ip224 with a level of --35 dBm. The-amplified Omeience frequency can be monitored at Tp20gS. Another check of phase lock operation can be done by measuring the dc voltage o[...]

Malntenance - 4g4A/4g4Ap Servlce Vol. i 1st Converter Bias This procedure presets flatness for Band 4, Band 5, and Bands '1, 2, and 3,: then adjusts the Start (O Hzi Response amplitude and overall flatness. These adjustments should only be performed after replacem€nt of the Dual Diode Assem'bly in the First Converter. Test equipment nee[...]

Malntenance - 494A1494Ap Servtce Vol. 1 6-45 o o O o o o o I o o o t o o I o o o I I o o o o o o a a o o t a o a a o o o o o O a o o Table 6-9 EQUIPMENT FOR ADJUSTING FIRST CONVERTER BIAS AND START SPUR AMPLTTUDE Test Equipment Characteristics Recommended Tvoe vottm€ter Sinewave Gengrator (10 pV to )350 Vdc TEKTRONTX DM502A and TM SO0_series Powe[...]

Maintenance - 4g4A/4g4Ap Servlce Vol. I Flgure 5-27. 1st LO Ddyer board adjustment and test point locatlons. o o o o o a o t o o o o o o I t o o o I o o o o o o a a o t t I o o o O o o ) o o I o o Baseline Leveling (Video processor) a. Connect the test equipment as shown in Figure 6-28. Set the ALC switch on the RF ptug-in to the MTR position. Set [...]

o o a O a o o I o o I o o a t o o o o o o a o o o o o o I I a a o a I O t o o o I I o o Figurc 6-28. Baseline levefing tert setup. (6) Adjust R1069 for a triangular waveform across the screen. See Figure 6-g1b: f/) Reset Rl0tg through Rl061 to midrange. (8) Sweep Band 4 in 2 GHz increments. Set the Spectrum Analyzer as foltows for th€ first 2 GHz[...]

Malntenance - 494A/494Ap Servlce Vol. 1 Figure 6-29. Typlcal basellne teveling response. o o o a o o o t o t o o o I t o o o o I a o o o o I a o o t t a o o o a o o o o o I o a (7) Activate View A, View B, and MAX HOLD. Note the response as th€ oscillator sw€eps. (8) Activate SAVE A and deactivate MAX HOLD, then select CW Marker on the Sweep Os[...]

Malntenance - 494A/4g4Ap Service Vot. 1 Figure 6-30. Easeline leveling adiument and test point locations. o o a o t o t o o o I a o a o o o o a o o a a o I I I o o t o a a o o I I I t a I a a I 106l (low) through R1013 (high) leyete, actiustments I t. ,l tl ll /1 It tt tt I n 'l -f I I 1 I t I tt U .u. I I 'f ltl -s { { at < - 4 { -71 [...]

Maintenance - 494A/4g4Ap Servtce Vot. 1 a o a a o I I a o e o a o o o o o o a t o o o o o t a o o , t a a o o o o o t o O I o o MICROCOMPUTER SYSTEM MAINTENANCE Several maintenance aids are built into the micro- computer syst€m. Th€se operating tssts dEmonstrate correct performance or indicate the location of a prob_ lem, if any. The switch set[...]

o I t I I I o I o t o t o o o o o a o a o a o o t a I o t t o I a o o t t 3 o o o a I t Microcomputer System Test .The microcomputer system test is chosen by setting switch #8 ctosed and switch #7 ogen in S1O6O. fni display is inoperative while this test is being performed. The microcomputer reports th€ t€st results via the LEDS on the GplB boa[...]

Maintenance - 494A/494Ap Service Vot. 1 !. A" microcomput€r next tests U2015, a timer chip on th€ Procassor board. lf any of the timers in U201b result in timo d€lays that ar€ too short or too long, the test stops with LED DS10Sg on th€ GptB board tit. 6. The microcomputer resets the GplA, U2050, on the GPIB board and checks to see t[...]

o o o a t o t I a o o O o I o o o o I I o a o o I a o o o I o O t a a o o o I o o a o a Processor Address Decoder _ Address decoder U3035 on the processor board decodes severd chip_ sel€cts. Y0, Y'1, y5, and y7 are shown in relation to the T/6-line in Figure 6-37. Flgure 6-33. Four maln bloack select outputs ot address decoder U20tf5. Mainte[...]

Instrument Bus Test lf the microcomputer performs the power-up self- test, but fails to properly control the instrumeht, the instrument bus interface may be faulty. Select the instrument bus test by setting the option switch as shown in Table 6-10. The microcomputer continuously writes to the instrument bus in a repetitive mannert so the instrument[...]

Malntenance - 4g4N494Ap Service Vol. 1 ADDR (instrument bus address) command These commands and queries are transmitted to the !ryl*rn Anatyzer with ihe pRtNT st#ment. rne upecrrum Anatyzer resp-onse to a query is input into a string variable with the tNpUT statement. A string vari- able is-formeclpV endinO th€ variable name with a doilar sign ($[...]

DATA (instrument bus data) query l F--{ oaraz }-.- - :^p0RjdglE*tF' 4416-08 Response to DATA query a4t$09 Combined ADDR command and DATA command Malntenance - 494Alttg4Ap Service Vol. I The address command may precede a data com- mand or query to identify the instrument bus location as part of the same m€ssage. Enors related to these comm[...]

G. Sweep (refer to diagram 3l) The microcomputer writes to registers 0F and 1F to control sweep rate, mode. holdott, interrupts, and triggEring. H. Span Attenuator (refer to diagram 32) Registers 75 and 76 control the span attenuator. l. lst LO Driver (refer to diagram 33) Register 72 controls functions on the 1st LO Driver board. Register ZE is ad[...]

Maintenance - 494A/494Ap Service Vot. i Table 6-13 (cont) Data Bits 76543210 Description C. Vldeo Processor (7C) 011xxxxx 001xxxxx 1l1xxxxx 010xxxxx D. Dlgital Storage o o o a a t t a o I o I o a o o o o I o o o o o o o o a o I o o a e t I o o o o o e o a xxx0000x xxx0001x xxx1001x xxx1101x xxx0011x xxx1011x xxx1111x xxxxxxxl xxxxxxx0 l xxxxxxx 0xx[...]

Data Blts 76549210 D. Digital Storage (cont) DB7-DBO DB7-DBO x1'lxxxxx xl0xxxxx x0lxxxxx E. Z-Axls & RF Interfaee Maintenance - 494A^l494Ap Service Vot. 1 Table &13 (cont) Table &13 {cont) Deseription Ver$cal Digltal Storage Board FA Data values from digital storage. A write to 78 initializes output to begin at the left of the trac[...]

Table 6-13 {cont) Malntenance - 494A/4g4Ap Servlce Vol. 1 Data Bits 76549210 Descriptlon G. Sweep I o o o I o ) t o o a o o o o I o I o 3 a o o o C o o o o a o o o o o o o a a O o o t o xx00xxxx xx0lxxxx xxl0xxxx xxxx00xx xxxx0lxx xxxxl0xx xxxxllxx xxxxxxlx xxxxxxxl 0 0 0 0 0 0 1 1 xxx1101 xxx1O11 xxx1001 xxx0101 xxx0011 xxx0001 xxx1100 xxx1010 xxx[...]

o o C o I o o C o o o o o a o I O t o J a o o a o o t o t I o o o a o o o o a o o a I o x x x x x x x x x Data Bits 7654321A J. Preselector Driver (77) 0lxxxxxx l0xxxxxx 00xxxxxx xxlxxxxx K. CENTER/MKR FREQUENCY Con- trol lxxxxxxx 0xxxxxxx x0xxxxxx xx0xxxxx xxx0xxxx xxxxxx0x xxxxxxx0 DB7-DBO D87 DBO L. Auxiliary Synthesizer Control (7D) DB7-D84 DB2[...]

Malntsnance - 494A/494Ap Servlce Vol. l Table 6-14 AUXILIARY SYNTHESTZER VALUES AS A FUNCTION OF N AND A Front-Panel Registers See Table 6-15. Table 6-15 FRONT.PANEL REGISTERS Writing Data to Shift Registers for Lights fi4) DB3-1 - Initiallzes encoder at power up Writing to register 74 loads data into shift registers that drive all the lights on th[...]

I o J o I I t I o O o ) I I J t o o o o I o o o I o t o o I o o I a J ) o o o o o a a I Maintenance - 4g4ful4g4Ap Service Vol. 1 TAPE DATA TRANSFER PROGRAM Macros stored in battery-backed up memory cannot be down-loaded to tape. consequenfly, the macros will be lost each time the battery is removed from ttre f_Aemory UoarO. lf the battery on the Me[...]

Maintenance - 4g4[l4g4Ap Servlce Vot. 1 1320 T1-t1+1 1330 Next i 13a0 S1:0 1350 Print 1360 Print 1370 Print 1380 For i-1 to 10 1390 Gosub 5000 1400 lf z-0 then goto 1400 1410 Print s1;'- Settings from Data File ";t1 1424 Goto 1440 14i10 Print s1 ;"-........ not written. FIL';TI;,. not used" 1440 S1-sl+1 1450 T1-t1+1 1460 Ne[...]

o o t o I I o o o t a t a I ) I a t o a t a o o t o o o o t ) o I o ) o o o o o o a o t 237A 2380 2390 2400 2410 2420 2$A 2440 3000 3010 3020 3030 3040 3050 3060 3070 3080 3090 3100 31 10 3120 3130 3140 3150 3160 3170 3180 31 90 3200 3210 3220 3230 3240 3250 3260 3270 3280 51-sl+1 T1-tl+1 Next i Print #a1:i$ Print Print Print "... FINISHED&apo[...]

Malntenance - 494[l4g4Ap Servtce Vot. 1 5000 ! Retrieve taped settings (s$) and send to memory tocations (s1) 5010 Z-0 5020 Delete var s$ 5030 Dim s$ to 6zt0 5040 Open #100:"FtL"&st6(t1)&'(ope-otd),, 5050 Input #100:v1,s$ 5060 lf v1-0 then goto SiSO 5070 lf Y-0 then goto 5120 5080 Print #a1:"RECALL ";s1 ;,';ReS[...]

o o o o t I o I o o o t o o t I o o o o o a a o t o o o o a a o o o a o a o o o o a o o 8110 Return 9000 ! This routine shows the contents of Memory disprays and settings 9010 Print "Disptay Memory', 9020 Print 9030 Print #al:,'ReS OFF' 9040 Delete var sg 9050 Dim s$ to 660 9060 Print #a1:"SET?' 9070 Input #at:s$ 9080 [...]

o a o o ? o o a o o o o O o t o o o o o a o o o o a o o o o o o o o I o o a t o o a o o[...]

O o o o o a o o o O o a o o o t a o o a o o o o o o o a o O a o o o o a a o o O a o o o First, Second, and Third Converters Swept-frequency anatysis is achieved by a triple- conversion superheterodyne technique. Each of 'the three frequency converters consists of a rnixer, a local oscillator, and appropriate filters. Only one frequency is conv[...]

Theory of Operation - 494A/494Ap Service, Vol. 1 main lF section for processing and detection. lF Section This section processes the signal for frequency resolution. Several functions are performed here: bandwidth filtering, amplitude calibration and loga- rithmic conversion, and signal detection. The 10 MHz lF signal is processed through one of se[...]

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o Digital Control Section Operational modes and internal functions of the spectrum analyzer are selected and controlled directly from the front panel. The modes anO tunctions that are selected are processed and activated by the instrument master microcomputer whic[...]

Theory of Operation - 4g4Ll4g4Ap Service, Vot. 1 DETAILED DESCRIPTION The following description is arranged by sections or systems; such as lst Converter, 2nd Converter, etc., followed by circuit analysis of the circuiis within that section. Each system or section is introduced with a description of the system using the section block diagram found [...]

o o o o o o o o o o o o o o o O o o o o o o o a o o o o o o a o O o o o o o o o o o o o _ The 2GHz Limit€r (A10) operates from 100 kHz to 2 GHz. lt has a linear two-port transfer characteristic of unity (-1 dB) until the input exceeds +5 dBm. Above this point, the internai detEctor OioOes conduct, reflecting part of the RF input energy back to th[...]

Theory of Operation - 4g4A/494Ap Service, Vot. 1 Directional Filter The Directionat Fitter (FL10) couptes the 2072 MHz signal to the 2nd Converter via low-pass and band-pass filters FLl1 and FL14. As mixing products iass through FL16, they induce a selected current into a one-wavelength distributed dng, which couples the 2072 MHz lF signat out to t[...]

Theory of Operafon - 4g4A/494Ap Servlce, Vot. i o o o o a o o I o o O o o o o o o o o O o o o o o o o o o o o o o o O o o o o o o o o o 2ND CONVERTER SECTTON (Diagram g) Two 2nd ConvErter systgms are used in the spec_ trum analyzer. One converts 207ZMHz to 110 MHz and the other converts g2g MHz to 110 MHz. The con_ verter used is determined by the [...]

Theory ot Operation - 494A/4g4Ap Servlce, Vot. 1 o o o O o o o o o O o a o o o a o o o o o o o o o o o o o a o o o o o o o o o o o o o o Figure 7-1. Ctpsr section of a four-cavlty filtee Selection between the two 2nd lF signals also takes place within the 829 MHz converter system. A diode switching network connects the active j10 MHz 2nd lF signal [...]

o o o a o o o a a a o o o o a o o o a o o o o o a o O o o o o o O o o o o o o o o o o o Theory of Operaton - 4g4A/4g4Ap Service, Vol. .l Figute 7-2. Equivalent circuit of the four-cavity filter. 2072MHz RF from.the four-cavity fitter (FL14) enters the mixer, where it is switched on anO off at a 2.182MH2 rate by the the mixer diodes. Both mixer diod[...]

Theory of Operation - 494A/494Ap Servtce, Vot. 1 Fllter to Mlxer RF Input Cable. Several products and harmonics of the local oscillator and RF input fre- quencies will exit the mixer via the RF input port of th€ mixer. The image (RF input minus the 2nd LO) and the sum (RF input plus the 2nd LO) are two significant pro_ ducts. There is enough ener[...]

a o o o o o I o o a o I a o o a o O o o I o o O I o o o o t , o a o I O o o o o o o I o amplifiers provide approximatety +10 dBm to the 2072 MHz 2nd Converter and +g dBm to the Reference Mixer. Sinc€ the two buffers are..nearly identical, only the 2nd Converter buffer is described. 'Oain is provicled by Q1011. printed elements provide input [...]

Theory of Operation - 4g4ful4g4Ap Servlce, Vol. 1 afray in the feedback loop of inverting amplifier ul073A. All of the amptifier's feedback is through R1072 when the output swings to the negative limit. As th€ output voltage swings less negative, it sequentially passes the tap-point voltages of a series of voltage dividers connected b€twee[...]

o a o a O o o I a o t I o o o o a o O a o o O o a o o o o o t a I a O a o o o I o o o o divide and offset lhe output of U1031 so the tune vol- tage ranges between 0 and -12.5 V. The output of divid-er Rl0gg/R1Og4 is apptied to the varactor of the 2192 MHz microstrip oscillaior (2nd LO). This closes the phase-lock toop, tuning if," ZnO LO so !l[...]

Theory of Operaton - 494A/4g4Ap Service, Vol. 1 Since the amplifiers are nearly identical, the follow- ing description applies to both amptifiers. The ac and dc signal paths are treated separat€ly. Figures 74 and 7-5 are simplified diagrams of the ac and dc signal paths. = 'PRINTED COMPONENT Figure 7-4. Equivalent ac circuit of an B2g MH: am[...]

o a o a o o O I I a a t o O a o o o t a o a O a a o o o t o O o t o o a o a o o o o o o _ The 3 dB pad helps ensure a consistent 5Oo inter- face for the 829 MHz Band-pass Filter. . T!" 450 MHz High-pass Filter btocks the tower lF signals generated within the mixer. . The mixer generates several intermodulation pro- ducts of the 829MHz RF and 7[...]

Theory of Opera$on - 4944/4g4Ap Servtce, Vol. I off. Negative current. supplied through Rl014, €nsures that Q1011 is turned off. Diode CRt011 protects the base of 0101 1 from excessive reverse bias. Voltage across R1017 is approximately 9.4 V when e1011 ls turned on and approximately 4.4V when it is off. Overall gain is approximately 12.9 dB when[...]

o a o I o I t t o o I t o o o o o t o a o o o O a o o o t a o a t o a o I o a o o a o o Because the grd harmonic of 719 MHz is locked to the 2182MHz reference, the tuning range ot tne 719 MHz osciilator is onty one third oithe tuning range of the reference. Since.th: rgnge is 4 MHz, ttre ringe-ot the 719 MHz osciilator is 71g Jt.gg trlnz. ' Th[...]

Theory of Operaton - 4g4A/4g4Ap Service, Vol. 1 to lock the difference trequency from th€ Harmonic Mixer to 25 MHz. The phase/frequency detector output is a voltage that is proportional to the phase difierence between the 25 MHz refer€nce and the lF signal from the g29 MHz Harmonic Mixer. This correction voltage is then applied to the 719 MHz V[...]

o o o t o o o I o O o I o o a o o a t o o o o o o o a o I o I o t o o o o I o o I o t a Theory of Operation _ 4g4Al4g4Ap Service, Vol. 1 3RD CONVERTER (Diagram 4) The 1t0MHz tF Amptifier (A32) and 3rd Converter (A34) down converts the ttO MHz ouiput signat from the 2nd Converter to 10 MHz for the VariaUie Resolution circuits. A 100 MHz crystat cont[...]

Theory of Operaton - 494A/4gdAp Service, Vot. 1 CRl029 added for maximum attenuation. lf Rl01 5 is set higher (nearer +i 5 V), diode CR3030 is forward biased and starts to conduct. Since the 2 mA supply current is relatively constant, this subtracts from the current through CRl02g. Thus, the impedance of the diodes is relatively constant, which res[...]

a o o I o I o I o o o I o o o O a a o o o O o o o o a o I o a o I a O o o o a o I a I a Calibrator u2022 and related components regulat€ a 100 MHz signat to -20dBm for the front-panet ill bUf connec_ tor. VRI 0S1 serves as an aecurate 6.2 V reference, which is divided to approximately 1.e V anO applied to pin 6 of U2022. The exact tevet ii set by[...]

Theory of Opera0on - 4g4[l4g4Ap Servlce, Vot. 1 Tune Amplilier .. Thg FET-input operationat amptifier (Ui034) takes the output of the phasefrequency d€tector, amplifies tJre gqgr and supplies an appropriate tune vottage to the 1O0 MHz voltage controlled oscillator. The tun€ ampliller, with feedback components c1031, c1o3g, Rl028, and Rl029, det[...]

o a o I o o I I o o a I I o I I I I t o a o o o o o o o a I e a t o o t I I o o o o o o Theory of Operation - 4g4ful4g4Ap Servlce, Vot. i Table 7-3 BANDWIDTH SELECTION Bandwidth DBO DBl DB2 3 MHz t MHz 100 kHz 10 kHz 1 kHz 100 Hz 10 Hz 1 1 0 1 0 1 0 00 11 10 10 0'l 01 11 Filters are selected by diode switching. Series and shunt diodes are at t[...]

Theory ol Operation - 494A/494Ap Sewice, Vot. 1 time. When a filter is selected, the series diodes are biased on and the shunt diodes are biased off. The diode conditions are opposite for the filters that are not selected. Since the switching operation is th€ same for all ftlters, the following description for the 100 kHz filter selection applies[...]

a o t a t O o I o o o I o o t o a a a o o o o O o a I o a I I a o o o I o I o o o a a I - -. The.assembly consists of four subassemblies: 1st Mix-er (A69A't), Bandpass Fitter (A69A2), 2nd Mixer (A69A9), and Local Osciilator (A69i4). These subass€mblies are on individual ciriuit boards con- tained in shielded compartments within a metal cas?[...]

Theory of Operation - 494A/494Ap Servlce, Vol. 1 After mixing, the l0MHz output signal is fittered with a second monotithic crystat fitter (y2020). This filter is important to the system operation. Without it, a large signal at 9.75 MHz woutd be present in the wide_ band VR amplifiers that foltow. Local Osclllator. The Local Oscillator assembly (46[...]

a a o a a t I t o o o I o O t o o I t o I o o a o o o o I o O a t o o a o I a o O o a t Theory of Operatlon - 4g4Al4S4Ap Servlce, Vol. 1 Table 7-4 GAIN STEP COMBINATIONS Band Leveting Circuit (Diagram 20) - The two amplifiers, in the Variable Resolution Band Leveling circuit, conect gain variations through the front end. These band-to-band variatio[...]

Theory of Operation - 49{A/4g4Ap Service, Vol. I The output of u3038A is apptied through edge con- nector pin BB to the gain control plN diode in the Band Leveling circuit. For example; when band 1 is selected (U3023 pin 1 low), current through Band 1 Gain poten- tiometer, R2031, and the emitter of e3036 sets the vol- tage through R2033 to the summ[...]

o a o o o t o o o o o I I o I o I o t o t o o a t a o o I o o a I o ) a o o o o o a a a .. fn9 input signat. at a nominal _14 dBm, is applied through toroid transformer T1041 to the Oaii of common-emitter amplifier el040. Gain adjustment Rl0i!0, in the emitter circuit. sets the posi Vn impfin"i gain. The output is transformer coupled, by Tt0i0[...]

Theory of Operation - 494A1494Ap Servlce, Vot. 1 Table 7-5 PROGRESSION OF GAIN REDUCTION Input Level Point 1 0.01 0.0316 0.1 0.316 Point 2 0.316 0.1 0.316 Point 3 Poinl 4 Beyond Logging Range x-10 dB 0.00316 0.01 0.316 0.1 - - 0'216 X Level X+10 dB X+20 dB x+30 dB x+40 dB 0.1 0.316 0.316 1-0.684-1 1.0 1.€ r-0.684 1- 0.684-_-1 1.0 1.684 l_ 0.[...]

o o o I a' a o I o a o I o o o a o o t , I o o I a I ) o I o a o I o t I O I a o o o o o . The 10 MHz input signal from the VR circuits drives input preamptifier e2075, in th€ tog lmftiner circuits on A62A1. - The input preamptifier ir"nsier" the S0O input signal to the high_impedance input of the first amplifier stage. The input s[...]

o I o o o o o o o o I a I o o I I a a a t t o I o o o o o o a o a a o a o t o o a a o o Theory of Operation - 4g{A/494Ap Servtce, Vol. 1[...]

I I o a a t o t o a o I o o o a I t o a I o o I o o I o t o o o I o I o o I o o a o o o Theory of Operation - 4g4ful4g4Ap Servtce, Vot. I DISPLAY SECTTON (Diagram 6) FUNCTIONAL DESCRT PTION The display section consists of the following major blocks: o Video Amplifier o Mdeo Processor . Digital Storage o Deflection Amplifiers . Z-Axis r CRT Readout [...]

Theory of Operaton - 494[l4g4Ap Servlce, Vol. 1 Figure 7-12. Selecdon ol display positlon on lhe log scale. Log mode amplifier U4030 tinearty amptifies the sig- nal. (fhe log conversion took place in the Log Amp cir- cuit.) At 2.2 V input, the output of amptifier U40S0 is 0 V. This is the only voltage at which the feedback cir- cuit switching netwo[...]

back loop for U5030 is now open. Diode CR5035 turns on to prevent U5090 from slewing too far negative. ldentily Circuit This circuit provides a vertical offset on alternate lllcg: t9 help identify truE and fatse signats. When the 'ldentify" feature is in op€ration, it allolvs the operator to distinguish between responses that result fro[...]

Theory of Operaton - 4g4Al4g4Ap Service, Vol. I Figure 7-13. Functonal dlagram rhowing the Spectrum Anafyzcr and 1405 TV Sldcband Ad.picr System. The product is converted twic€ more, amplifi€d, liltered, log amplified, and detected. This detectdO sig- nal is applied either directly to the video amplifiers of the crt or to digital storage. The S[...]

a o I o o o o o o t o I a o o o I o a a I o o o o o I o I o o o I a ? o O o a o o o I a Video Leveling . -A^mjnor slope in frequency response, caused by the 1.86 GHz low-pass filter in the front end, is corr€cted with band I Slope adjustment R1012. Wiren operatng in band 1, contacts 6 and 7 of U3025 are closed; therJ forq a portion of the PRESELE[...]

EXT VIDEO SELECT MARKER/VIDEO 15 VIDEO FILTER OUT 6, 11 INTERNAL VIDEO OATA BIT 1 RC FILTER u20158 Theory of Operation - 4g4A/4g4Ap Servtce, Vol. 1 o o I a e I f o o t t o o o o o o a o a t o o 'l o o a o o o o o a o I o o J I O o o I t Flgure 7-14. Simplllied diagram of a video filter. Tabte 7-6 FILTER COMPONENT COMBINATIONS Two signal inputs[...]

The filter consists of resistors R2O2g, RZOZ1, R2022 and capacitors C3026 and C2016, "onn""t"O between U3062 and U2066. Tabte 7-6 lists itre tiiiei components in thE circuit for each of the six OanOwiOttrs. Data bits 2, 1: "1! 4 are apptied to switch U2O15B (pi-ns B, 16, and 9) which selects the components. frorir U2OOOB, t[...]

Theory of Operation - 4g4A/4g4Ap Service, Vol. 1 Graphical presentation of mathematic functions or experimental data is common. one such graph has a single Y value for each X value. An alternaie presenta_ tion of the data in this graph would be a table simply listing the x coordinate values along with a correspond- ing Y value for each X value. To [...]

n I .l "l I )"t*^.ocr-t rl 'l o) __l_, I rEmal t+t^ I cfocr( I IqECR^ron FoD Theory of Operadon - 4g4N4g4Ap Servtce, Vot.l o a . o I o I o o o o o t t o I a t o c a o ) ) O e o o o I o o o o t o o o a o o t I o Figure ?-15. V.rtical confol lC block diagram,[...]

Theory of Operation - 4g4Ll4g4Ap Servlce, Vot. 1 As each new Y value is converted. it is added to the eight least significant bits of th€ numerator. Each carry from the most significant bit of this addition is counted by a 17-bit ripple counter. The contents of this counter and the 8-bit sum are cascaded to form a 25-bit grand total. Each time a [...]

t o ) o t t I o o o o o I I a o o I o I o o o a o o I o I t o o o o o o I D o o o a t o stored in the display shift register. Then, as th€ A value is- read. it is cornpared with the B value and the larger of the two is loaded into the disptay shift regisier. Finally, the number in the shift registei is writte; into memory._ This operation is perf[...]

Theory of Operation - 494A1494Ap Service, Vot. 1 combination with multiptexer U2020, suppties the CON- STANT data to U2030. Muttiptexer U2A2O is, in turn, controlled by address bits 0, 1, and 2 to provide the proper constant data bit to u2030. Output Clrcults. From the U2030 verticat display register, the parallel data output is applied to 6-Oit di[...]

Theory of Operafon - 494A/4g4Ap Servlce, Vol. 1 o a a o : 3 a o o I a ) ? 3 o o o o o o o o a o o o I o t I t o I o a a a o a o o a o o A INTENSITY BUS REG INTENSITY VIEW A vtEw I B-SAVE A SAVE A 1O BIT UP/DOTYN COUNTER[...]

Theory of Operation - 494A/4g4Ap Service, Vol. .l Marker lC. Marker lC U9020 performs several func_ tions on the Horizontal Digital Storage board: In conjunction with Horizontal Digitat storage tc U5020, it cr€ates the two waveform markers and the update marker. Controls the processor addresses assigned to digi- taf storage -7A,78, FA, and FB. Cr[...]

o o o t o t t o o a : t o o o I a o 3 a o a o a t o o o o o o o I o a o o o o o a o o o the 500 digital storage sweep positions. The resulting clisplay appears as a bright dot sweeping across the crt, rising and falling with the signat. The basic circuits consist of a set of latches, a digital-to-analog convert€r, a compar"toi, " pulse [...]

Theory of Operation - 494A/494Ap Servlce, Vol. 1 ing sid€ ar€ through the parallel combination of resis- tors R4049 and R4048 and capacitor C4057. The series connection of resistor R4049 and variable capacitor C4057 provides high-frequency respons€ compensation. Capacitor C2A7 controls high-frequency feedback. Input to the non-inverting side [...]

o o o o o o o o o o a o o o o o a o a o o o o o o o o o o O o a I o a o O a o o a a ? O change in input power frequency or power supply vol- tage and notifies the microcomputer.' en etapiid time meter is also located on the board to give a indication of total instrument operating time. RF lhterface Circuits The RF interface includes the digita[...]

Theory of Operation - 4g4[l4g4Ap Servtce, Vot. 1 Transistors Q1017 and Q1015 provide curr€nt for the trace rotation coil. Trace Rotation adjustment Rl021 sets the current so the displayed trace is aligned with the graticule. Power-Fail Detector This circuit detects an instrument power failure and transmits th€ information to the processor and M[...]

o o o o o o o o o o o o ? o o o a o o o o o o o o o o o o o o o O o O o a o o o o o o o CR4078 and CR40Z at the input to U4ogil, protect the input against excessive voltage excursions. The high-voftage osciilator is protected -Oy enfteft RgOTg, (d ?/ and R4074 in case the +i00 V suppi should fait. Nor_ mally, CR1037 is back biased. ti tne +t00V is [...]

Theory of Operatlon - 4g4A/4g4Ap Service, Vol. I READOUT ON TIMING CHARACTER GENERATOR CHARACTER COUNTER INSTRUMENT BUS R/O HORIZ DEFLECTION Flgure 7-17. Block diagram ot crt readout.[...]

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o Theory of Operation - 4g4Ll4g4Ap Service, Vot. l Figure 7-18. Character on/of timlng. Character counters synchronize the horizontal and vertical scan with the Z-Axis signal from the character g€nerator lC to draw the character. These counters, U2022, U2018, U2[...]

Theory of Operation - 494A/494Ap Service, Vot. 1 Figure 7-19. Charaeter scan. The counters are wired to torce the D/A converters to step through the character horizontally, a row at a time. At the same time, the pattern of dots is accessed under the control of the timing decoder logic, U2O39B and U2031. The AND gate and decoder combine to controf t[...]

1-OF-64 DECODER 54 CHARACTER ROM LINE COUNTER/ SHIFTER SHIFT REGISTER Theory of Operation - 4g4[l4g4Ap Servlce, Vol. 1 Flgure 7-20. Character generator block diagram. o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o O o o o o o o o o o o o o[...]

Theory of Operatlon - 4g4A/494Ap Service, Vot. 1 Flgure 7-21. Character timing dlagram. o o o o o o o o o o o o o o O o o o o o o o o o o o o o o o o o O o o o o o o o o o o o lnstrument Bus Interface The microcomputer controls the crt readout and fre- quency marker dot over the instrument bus through the following ports. Decoder U3051 asserts 5F w[...]

o o o o o o o o o o a o o o o O o o o o o o o o o o o o O o o o o a a o o o o o o o a o U10418. Also, when th€ ON/OFF tine goes high, it €nables the |NCR gate, UlOgTC, to steer-the poiition counter onto the character RAM address inputs through fine driver U3042 and muttiptexers UI050 and U1046. When cleared, this bit places an address, latched [...]

Theory of Operaton - 494A/494Ap Servicg Vot. 1 U1016A delays the marker dot to allow retrace white gating DOT INV low to set up th€ disptay. DOT tNV afiects th€ readout deflection outputs in the fottowing ways. 1. The horizontal output is connected either to ground, for a center-scr€en dot, or MAX DOT CON- TROL, for a max span pointer. MAX DO[...]

o o o o o a o o o o a O o o o O o a o o o o o o o o O o t a o O O o I o O o o o o a O o Theory of Opera$on - 494[l4g4Ap Servtce, Vol. 1 Flgwe 7-22. Frequency dot ma.ker simprified diagram with timing waveforms. ___r- r Fimvf +--i_-R/ooFF "^foT*---r I lla.x SPAN+------{ , .Dro{r€ Al{o" GAIE cFr013 c81012 ct01 r R1015 R€tn^cEoil€-sHor[...]

Theory of Operaton - 494A/494Ap Service, Vol. 1 The Frequency Control section performs the tuning and scan function for the preselector, l st LO, and 2nd LO. lt also provides the sweep voltage for the deflection amplifiers in the Display section so the crt display is coincident with the frequency scan and tun- ing. This section contains the followi[...]

o o a o o I o o o a I o o t o I o o o a o o o o o o o o I o o o a o o o O o o o a o o o The digital control circuits receive and decode the address and instructions from the microcomputer, select the . sweep rate, holdoff time, trigger sourcer sweep mode, control marker dac, and cont?it interrupts to the microcomputer. .^.I"_I:rIT. DAC provide[...]

Theory of Operation - 494A/494Ap Service, Vol. 1 Tabte 7-12 TRIGGER SELECTION MODES Trigger Mode Free run Internal Ext€rnal Line Table Z-13 SWEEP HOLDOFF SELECTION Sweep Holdoff Short Medium Long Sweep Generator The sweep generator is an integrator circuit consist- ing of operational amplifier U10S5 with one fixed and two switchable capacitors in[...]

o o a o a o o o o O o o o a a o a o I o o o o t o o a o O I o a O o o o o o o o o o o o Marker DAC The Marker DAC circuit provides a dc level corresponding to the marker sweep position. This occurs during retrace. allowing osciliators to operate long enough for the counter to get an accurate reading gJ the marker position. The processor loads twelv[...]

Theory of Operatlon - 4g4A/4g4Ap Service, Vol. 1 Sweep Holdofr During retrac€, the sweep must b€ held off long enough for the timing capacitors in the integrator to discharge and the circuit to stabilize. To prevent flicker, the holdotf period must vary as sweep tim€ changes. U30258 and three timing capacitors (C3027, C3030, Lnd C3032) plus a[...]

o o a o I O I a o o a o o I a I O o I a o o I a a o O O o I o o I O o a a o o o o a o o SPAN ATTENUATOR (Diagram 32) The span Attenuator selects the appropriate attenuation factor for the incoming swe€p signal, to establish the frequency span. The span Attenuator con_ s-ists of digital control circuits, which receive and decode the address and in[...]

Theory ol Operaton - 4g4A/494Ap Service, Vot. 1 R2 Rl 1ok t, I 20k . I s1 4114122 Flgure 7-23. Simplified digital-to-analog convertGr, o o o o I a o o o o o o o o o ) a o I t o o o a o o o o I I o o o o o o o o a o o o o o Feedback for the output stage is provided by R1056, plus an internal resistor in U1042. The internal feed- back resistor ensure[...]

o O I o o o o o o a a a o o t a o I a a I o o a a o o a a a t I o a o o O o o o o o o I The 2" side of U4025 is contro[ed by data bits, DBS and DB6, on the e6 and e7lines trom deotS. The ,,2y, outputs of U4025 are applied through buffers in u4042 to select the appropriate attenuation factor for the out- put sweep. Table 7-1S lists the stat€s[...]

Theory of Operafon - 494ful4g4Ap Servtce, Vot. 1 r The mixer bias circuit produces and outputs the required bias voltages for the 1st Mixer. . The programmable bias circuit provides peaking voltage for the Preselector or external mixers bias voltage based on data supplied by the microcom- puter. Digital Control The digitat control circuit controls [...]

a o a o I I o o O o I o o o o a a o o o t t o a a o I o a a o o I o o I a o o o a a I o the amplifier. This in turn, changes the current drive to the oscillator coil. Reference Supply - ., Preamplifier e2052 plus amptifie r lJ20S2 and emitter follower Q2051 , are the active compon€nts of th€ _1 O V I-ej9fl"":.uppty. Bias for one sid&a[...]

Theory of Operaton - 4g4A/4g4Ap Servtce, Vol. 1 o The tracking adjustment circuit, which compensates for different preselector sensitivities, compensat€s any pres€lector offset, and compensates for non- linear operation caused by magnetic saturation of the Preselector. r The final driver stage, which changes the applied signal voltage into a cu[...]

I o I o a o o o o o o , o o o I o o o I t o e o o O I o a a I I o a I I I o o o a I a o lF Ofiset The -10 V reference, from the oscillator driver, fur_ nishes the precise reference vo,tage for the lF offset circuit. Since the offset voltage is pioportionat to the lF mings 2.072 GHz, no ottset id requireo for the +2.072 GHz tF. FET 02094 adds th€ [...]

Theory of Operation - 494A/494Ap Servlce, Vol. 1 Current Driver This stag€ consists of the output stage 0565/05052; FETs Q3061, eg077, and e2074: amplifiers U205,4 and U3054; and transistor e4097. When the Preselector is not in use, DB2 goes low and turns Q2074 ofi to reduce the coil current to zero. Preamplifier U2054 reduces the temperature dri[...]

I o o O a o o t o o I , o o o o a t t o I o a o o O a o a I o I o O t O I o o o o o I o lf the high-order device operated with no overatl linearity inaccuracy, the operation would now be com- plet€ and the low-order incrementing could occur. However, th€ DAC device can vary byine LSB of the correct value. Figure 7-25 illustrltei a graptr of the[...]

Theory of Operaton - 494[l4g4Ap Servlce, Vot. 1 Figure 7-26. Simplilied tune voltage converler. a o o o I a t o o a I I o O o o o O a t o o o a o o I o a , o a a o o o o o o o o I a o In addition to ihe six steering lines that drive the steering gates, U4025 also supplies the trackc (coarse) and trackf (fine) lines, which control the track/hold sel[...]

I o a o a a o o o O I t o o I o o o a a t o a o a C I o I o o I I e a o I o o o o o a o .Data from U4035, the data buffer, is clocked into the registers each time a difierent tune voltage is required. U3050 feeds the lowest eight bits to thE liw-order DAC, u2055; U3070 teeds the higlgs1 eight bits of the high- order DAC, U2060. Registei U3060ieeOs [...]

Theory of Operalion - 4g4A/4g4Ap Service, Vol. 1 Low-order DAC U2055 tunes approximately +2.5mV at pin 1. and its gain is adjusted by R1O2S. l!e^ gain oj p-r_elmplifier U1065 is set at approximatety 10,000 by Rl056 and the 5O combination of R2O59 ana R2060. The combination of CR1056, CRlO58, RlO54, and R1059 limits th€ gain of U1065 when the outp[...]

I o a o o a o o o o o ) o o o a a I t I I o o t o o I o I o o o o e o o I o o o o a o o Theory of Operation - 4g4ful4g4Ap Service, Vot. 1 100 MHz reference signal from th€ grd Converter, is divided down to 25 MHz, on the Synthesizer board, and applied as the reference signal to the mixer on the Offset Mixer board. The 25 MHz signal is also applie[...]

Theory of Operation - 4g4A/4g4Ap Service, Vol. l puter tunes the l st LO frequency through the following sequence; up 750 kHz, down i.5 MHz, up 1.5 MHz, ani down 750 kHz. During one of these yirmware searches,' the lst LO frequency passes through the strobe har- monic frequency and th€ loop acquires lock. Any frequency difference between the[...]

I t a o o a a t o o o t I o o o a o o I o o o o o o o o o t a o I o a I t I t o I o a o Theory of OperaUon - 494Al4g4Ap Servtce, Vot. 1 Output Amplifier LO AIIPLIFIER 4416-200 Flgute 7-27. Slmplified schematic of harmoolc mixer. Two additional directional couplers are used to cou- ?f..lh" 1-9c!. signat into the mixer circuit. A power ll,ll&quo[...]

Theory of Operation - 4g4A/494Ap Service, Vol. 1 PHASE/FREO DETECTOR fr:t,orF:NF, Figure 7-28. Block diagram of a baslc syntheelzer. Phase/Freq DETECTOR mOD CONTROL F,n : (NP + A) Frct o a t o I o o o o o t o o o o o o o o I o o o a o o o o o a C a o a o I o a o O o a o O Figure 7-29. Basic block diagram of a +N syntheeizer with a variable modulue [...]

This synthesizer uses a variable modulus prescater to divide the VCO frequency before is processeO by the "+N" counter, such as shown in Figure 7-29. The vari_ able. modulus prescaler is iontroilej by a moclulus con_ trol input. When the line is high tne pr6scater is a divide by P+l and when the tine is l6w the division cnange" to P.[...]

Theory of Operaton - 4g4Ll4g4Ap Service, Vol. 1 CR2068. CR1065 provides a clamp to prevent a control line voltage less than 5 V. Capacitor C1070 sets the low end of the control voltage to about 6 V. Range of the control voltage, over the 20A-Z2O MHz VCO ,ing", is about *6 V to +11 V. The off/on status of the VCO is controiled by U4074 which is[...]

DBl-ThE N LATCH signat for the lst LO phase tock is sent on this line. DB2-Reserved for future apptications. DB3-This lin€ resets the buffer sequencer at the outsEt of a talk cycle for the counters. DB4-This tine (CONTROL LATCH) tatches a conrrot word into the output buffers ot VZOZS on the Error Amplifier board. DBS-This signal clears all the co[...]

Theory of Operaton - 4g4[l4g4Ap Service, Vol. 1 The Synthesizer can be divided into three functional blocks: the 100 MHz divider, the SO MHz divider, and the -+N counter. The 100MHz divider consists of flip-flop UgOgOA and transistors Q3040 and e3041. The 100 MHz signal from the 3rd Converter stags is applied to the clock input of u3030A. u30308 fu[...]

U10508 witt ctock first, placing a high at the Error Amptifier,s inverting input. This iamps it," "*ptiR", ort- put low untit U1050A switches d "iiort time tater. U20508 resets both flip-flops anO tne inner toop error amprifier wiil stop rampin! untir the next correction cycle. At the next col-1clion cycle, the error amplifier w[...]

Theory of Operation - 4g4[l494fup Servlce, Vol. 1 drifts negative, the other half of UlO.l5 conducts, caus_ ing reverse action to occur. - Normally, the input signal to the window comparator is attenuat€d by R2040, which reduces the voltage applied to U101S to 0.9% of the output from U204-g. This allows U2048 to drift up and down without immedi- [...]

...Ttg V_CO output !g apptied to the ctock input of divide-by-s counter UaZZ. 'The STROBE'er.raeLe fin" frgm tlte Error Amplifier permits the counter to operate when the line is low and is the means by wnich the microcomputer can turn the strobe pufsed on or off. The .counter output couples throug'h an- impedance matching networ[...]

DIGITAL CONTROL (Diagram 9) The Digital Control section provides operator and digital controller interfaces. lt translates changes in front-panel controls and, for the programmable version, also translates instructions received via the GplB into codes that control the instrument. The user interface to th€ digital control operating program is disc[...]

Theory of Operation - 4g4Ll4g4Ap Servlce, Vol. 1 o o o o o o I o o o I t o o o o o t o a o o 3 O o t t o I o o o o I t o o o a o o ) o o 8000 7800 7000 4000 0000 Figure 7-30. System memory map-[...]

Theory of Operation - 494A/494Ap Servlce, Vol. 1 DTA PFESENT DT REOUEST ilA GRANT feoc SWP CATE TMER sNO oPrg sRo SER RgO PWR FAIL lililililll NEAR PANEL GP|a SIVITCH (P VERStOfl ONLYI -__ ,-7 Llllllull,l ITISTRUTE'{T oATA 8US INSTRUTIEilT AOOfi€SS aus TIMEN SRO 02 CLocK I/O SPACE MEMORY MAP + EPnoti SYSTET fiA'U I I I ? +- -- 7E@ +--+ [...]

o o o o o o a o o a I o o I a o t o o o O a o a o t o o o I o o o I o o t o a o o c o I Theory of Operation - 4g4hl4g4Ap Service, Vol. 1 Figure 7-32. PIA and Timer address map, 6821 PIA REGTSTERS OATA VALID 0{sTRUt|€XT D^TA AUS POLL II{STRUTIENT AOOR€SS BUS AODRESS RANGE !O.FF N€ADFROT'NSTRUilEilT (n-7F WR|TE TO tilSTRUit€ltT 6840 TIME[...]

Theory of Operation - 494A/4g4Ap Service, Vol. 1 Clock. This circuit generates the clock signat that drives the microprocessor, the GplA transceivdr on the GPIB board (A56), and the character generator circuitry on the CRT Readout board (A66A1). Y1030, Q2035, and e1030 form a clock circuit that oscillates at 3.4133 MHz. e2095 and y1030 form a Colpi[...]

a o a a a a o o a o o I o o a I ) o o o o , o I o o t o I I I a o o o o o o o o a o I o GPIA interface circuit on th€ GptB board (A56). (Ihis only occurs on the programmable version.) Before each transf€r, the microprocessor loads U1020 with the starting address of the RAM data and the number of data bytes to be transferred. When the GPIA inter[...]

Theory of Operation - 494Al4g4Ap Service, Vol. 1 lf the PwR FAIL line returns to a high state before the microprocessor is reset, the microprocessor does a power-up initialization to ensure that the instrument operation will not be affected by a temporary power loss. This power fail sequence can be disabled by remov- ing jumper W2035. This may prev[...]

o a o a o a t I o o I t o o a I ) o a o t a o a o C t o t o t o o a a a t o o o o o o o lithium battery 8T2040, or in option 3g, silver batteries (Eveready 392 or equivalent). See the Maintenance section for replacement information. Each ol the non-volatile memory lcs require less than 2 rl. They wiil hold. data as tong as the battery voltage is ab[...]

Theory of Operation - 4g4[l4g4Ap Servlce, Vot. 1 ROM. The ROM in this instrument is located on this board and on th€ ROM Banks & GptB board (A56). The ROM consists of system ROM containing the instrument operating system and the program RoM containing the various measurements routines and crt messages. The system ROM is always accessible, whi[...]

o o o o o o o o o a a o o o o o o a o , o o o o o t o o I o a o I o o a a I o o o a o o Accessories lnterface (Diagram 44) The Accessories lnterface board (A90A76) provides access to the instrument bus, and the external MARKER/VIDEO input and controt tine. The MARKERIVIDEO input is through a coaxial connector. The other lines are availabls through [...]

Theory of Operaton - 4g4[l4g4Ap Servtce, Vot. 1 appropriate action. Th€ following is a description of the hardware and a brief description of the software used bythe front panel CPU. Potentiometers. The following controls or adjust- ments generate analog signals used by other functions of the instrument. These controls are non- programmable. INTE[...]

O o o o o o o o o o o a o o o o o o o o O o o o o O ) o a o o o t o o o o o O o o o o o will see a phantom closure at y2lxg as it scans the key matrix. To suppress these piantom key closures, diodes have been added in series with the RESOLU- noN BANDWTDTH, MtN RF ATTEN, SpAN/D|V, and gerta]l other keys in column 6 and 7 of the k'ey matrix. In [...]

Theory of Operaton - 494[l4g4Ap Service, Vot. 1 Keyboard Check Subroutine. This subroutine is called when the main scan routine detects a change in the keyboard matrix which occurs when a key opens or closes. A key opening usually signifies that an action has been completed, whereas a closure indicates that an operation or action is requested by th[...]

Theory of Operation - 494A1494Ap Sewice, Vot. .t DATA ENTRY kHz/-dBX 5 1 6 I HzldB MHz/+dBX ROW o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o a o o o o o o o 2 4 3 7 X1 X1 X1 x1 X1 X1 X1 xl x1 X1 ,<2 ,<2 x2 x2 ><2 x2 x2 )<2 x2 x3 x3 x3 x3 x3 x3 X3 x3 X3 x3 x4 x4 X4 x4 x4 x4 X4 x4 x4 x4 X5 X5 x5 X5 X5 x5 x5 X[...]

ROW coL HEX CODE MAIN FUNCTION <BLUE.SHIFT> FUNCTION <GREEN.SHIFT> FUNCTION DATA ENTRY X6 X6 X6 X6 X6 X6 X6 Y1 Y2 Y3 Y4 Y5 Y6 Y7 32 33 34 35 36 37 38 MIN RF ATTEN dB 0 10 20 30 40 50 60 X6 X6 x6 Y8 Y9 Yl0 39 3A 3B RECALL AF COUNT STORE (settings) MKR - CENTER COUNT RESOLN BACKSPACE x7 x7 x7 x7 Y1 Y2 Y3 Y4 3C 3D 3E 3F FREQUENCY SPAN/D|V [...]

Theory of Operation - 4g4A/494Ap Servlce, Vol. 1 o o O o o o o o o O o o o o o o o o o O o o o o o o o o o o a o O o o o o o o o o o o o POWER SUppLy (Diagram 10) The Main power Supply furnishes all the regulated voltages for the spectrum analyzer, exc€pt the crt high- voltage :uppty. The high-efficiency desiin of the Main Power Supply reduces to[...]

Theory of Operaton - 494A/494Ap Servtce, Vot. 1 u$36. PrN 2 u603A PIN 3 u6036, P|l{ 7 Figure 7-34, Primary .egutator Input and output waveforms. a o o O o o o a o o o o o o o a o o o o o o o o o o o O o o a o o o o o O o o o o o a o Ramp Generator. The ramp generator circuit is a gated sawtooth generator that consists of T6044. Q5023, Q6034, Q5032,[...]

O o o o o o o o o o o o o o o o o o o a o o o o o o o o o o a O o o o o o a o o o o O o Theory of Operation - 494[l4g4Ap Servlce, Vot. 1 Flgure 7-35. Tirning waveforms for soft-start clrcuit Inverter Driver. The inverter driver consists of transistors Q6072 and e6079, transformer T60g1, and related components. This is a push- pull amplifier with di[...]

Theory of Operation - 4g4Ll4g4Ap Service, Vot. 1 Secondary & Fan Drive Circuits (Diagram 47) The secondary circuits include the rectifier_filter cir- cuit, which rectifies and filters the secondary voltages; the voltage reference circuit, which furnistrei a stiOte and precise reference for the regulators; and the regula- tor circuits, which con[...]

o o o t I o o o o o a o O o a o O o o o o o o o o o I a o o a a o a o o a a a o o o a o Fan Drfve Circuit The fan drive circuit provides a temperature- con- trolled current drive to the fan motor. if,e circuit pro- 1y:?: " thr€e-phase_drive culent of approximatety 240 Hz operating freguency. The actuar ctrive circuit operates as a ring count[...]

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o o a I o o o a o a o o o I O o o o o o o o o o o o a o o o o o o a o o o a o o o o o o OPTIONS This section describes the options available at this time .- for the spectrum analyzer. Ct.ng"" in specifications,.if any, are described in this section. Con- taet your local Tektronix Field Office or representativ€ for additionat information[...]

OPTION 07 ALTERNATE SPECIFICATIONS Within 2ao/o ol selected bandwidth *2.0 dB about the midpoint between two extremes +20 dBmV *0.5 dB at 100 MHz Optons - 4944/494Ap Servlce, Vol. 1 Option 07 (75O Inpur) Option 07 provides an optional 7SO input and *20 dBmV calibrator in addition to the standard 50O input and +20 dBm calibrator. Also, a 300 kHz Res[...]

o o a o o o o o o o O o o I o o O o a o o o o o I o o o I o a o o o O o a o o o o o o I Optons _ 494Al4g4Ap Servtce, Vol. 1 Tabtc B-2 (Continued) OPTION 07 ALTERNATE SPECIFICATIONS tS.4GHz to l2 GHz. bl2 GHz to 1g GHz. Options 21 and 22 (Waveguide Mixers) Option 21 includes a set of hrvo high-performance waveguide mixers (18 to 40 GHz). Optio-n i2 [...]

Optione - 494A/494Ap Service, Vot. 1 Option 39 (Sitver Battery) . Option 39 provides a silver battery for the instru_m€nt's battery-powered memory. The battery life at +55"C is 1-2 years and 2-5 years at +2SoC. W€ recommend removing the silver batteries during long- term storage. Option 41 (Digitat Radio) Option 41 inctudes the follow[...]

o a a a o o o o o I o o o I o o o o o o a o o o I o a o o O a o a o I I a o a a O o o a Opdons _ 494A/4g4Ap Servlce, Vol. 1 Tabte 8-5 OPTION 42 ELECTRICAL CHARACTERISTICS Characteristic Performance Reguirement Supptemental Information tu Mnz tF gutput Center Frequency goesanoffi B"ndp""" C[ptJ-- symmetry "ooultn"Gffi q[...]

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o o a a O o a I o t o O o o I o a t o o a o o o o a a o o o a o o o o O o t I o o o o I GLOSSARY .._-Il"^^1"_l':,*ing gtossary is presented as an aid to understand the terms as they aie used in thi" do"urn"nt and with reference to spectrum anatyzers. GENERAL TERMS Center Frequency. That frequency which corresponds to t[...]

FREQUENCY TERMS Display Frequency. The input frequency as indicated by the spectrum analyzer and expressed i; hertz. Frequency Span (Dispersion). The magnitude of the frequency band displayed, expressed in-hertz or hertz per division. Frequency Llnearity Error. The error of the relationship between the frequency of the input signal and the fre- que[...]

o o o O o o t o o t o I o O o o o I o o O o o a o a o o I O I o I o o I I o o O o o o I Sensitvity. Measure oJ a. spectrurn analyzef s ability to display minimum rever signars, "*pi".J"o in vorts or decibets. Intermediate. tr"qu"n"V -ifei bandwidth, display mode, and any other innueniinji"'.to* must be given.[...]

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o o a o o o o I I o O I o o I o o I o o O o o O a a t o t a I o o O a I I o I o o O o I REVISION INFORMATION Manual Part No. 07G556O-00 Flrst prtnilng JAN 1987 hduct Revleed Manual Insert Status CHANGE REFERENCE SEP 1987 FEB 1988 MAY 1988 JUN 1988 MAY 1990 JUN 1990 SEP 1991 c11887 M63911 c2lsge M66071 c21590 C2l590 REVISED c1-991 Effective Effectiv[...]

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Tektronix. Cornnt|ncd to Ercdl€E Date:9-1-87 Product: See list MANUAL CHANGE INFORMATION Change Reference: C1 1887 Manual Part No: See list product Group: 26 INSTRUMENT 494N494AP Op€rators 494N4944P Service 1 Part No. 070-s557-01 070-5560-00 gN 8010227and up Feplaca sanshlvlty table In the speclflcailon secilon wlth the tabte betow. SENSmV|TY o[...]

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Tektronix" Cdmfrittsd to Erca{ence Date:2-22-88 Producl: see list MANUAL CHANGE INFORMATION Change Reference: M6391 1 Manual Part No: see list product Group: 26 I a I o o a o a o I o o o o a o o I ) o o t a O o o a o a o I o o o o o a O o o o o t t Inslrument 4941P service 1 495/P service 1 49?NAP service 494AIAP service Manual 070-4416-00 070[...]

Product: see list Date:2.22-88 Chg. Ref. M63911 J. Set the Spectrum Analyzer controls for a lriggered sweep, then switch the sweep oft by activating SINGLE SWEEP, and ensure READOUT is on. K. Monitor lhe drains (metal tabs) of 04040 or Q4030, on lhe dellection Amplifier board, with test oscillo- scope. See Figure 5-6 L. Adjust C1040 for best freque[...]

o o I o o o o o o o o I o o I o o I o a o o o o o t o o I o I O o o t o o o I o o o o I Product: see llst date:2-22-88 Chg. Ref: M6391r Replace the description for the Deftection Amptifiers (Diagram 27) with the tottowing. DEFLECTION AMPLIF|ER (Diagram 278) Refer lo ihe block diagram adjacenl to Diagram 27 as well as the schematic diagram. The Defl[...]

Product: see llst Dale:2-22-88 Chg. Ref: M63911 The standing cunent on the horizontal amplifier Moslets is established by a resistive divider R4046, R3045, and R5038 as lollows. The base of Q5040 is set 3.5 volts negative wilh respect to the +300 volt supply. The voltage drop across 85045 is then 3 volts and the resulting emitter currenl is 2.0ma. [...]

Product: see llst Chg. Ref: M63911 Replace tigure 5-6 in the Adjustment procedure section with the following diagram Figure 5-6. Deflection Amplifier test points and adjustments o o o o I a e o o a o I o o o t I o t a o I a a o t o o I o I o o O I o O I I o o o o o Def iectron Arnplif ier Horl Zontal freqJency response Page 5 ol 5[...]

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-^l-.r-- - r teKtrontx, Conmined to Erca$eno Date:5-1G-Bg Product: See List ITIANUAL CHANGE INFORMATION Ghange Reference: C2t5lgg Manual Part No: See List product Group: ZO PERFORMANCE CHECK PROCEDURE o a o o o o G a o o o I o o o o o I I a O a o o o o o o o o I a a o o o o o ) o o o o a INSTRUMENT 49UP Seruice 1 492P/6 Service 1 4941P Service t 49[...]

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Tektronix. Cottrti.d to Ercrltono Date: $01€8 Product: See list MANUAL CHANGE INFORMATION Change Relerence: M66071 Efi/SN 8010100 Manual Parl No: See list produci Group: 26 o a o o I o o a o o o a o o o o a o o I t I a a a o o o o C o O o o T O o o O a o o o I INSTBUMENT 494NAP Operators 49YP Operators 2753P Operators 27541P Operators 2756P Opera[...]

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Tekt"fp"n[X. Date: 5/u9o Product: 494N4g4Ap Service Vol. 1 MANUAL CHANGE INFORMATION Change Reference: C2lSgO ManualPart No. 070-5s60-OO product Group: 2E In section 4 - PERF)RMANCE )HECK pRocEDURE change step r r as foltows: Replace header secfian with the foltowing: 11. Check Resolution Bandwidth and Shape Factor (bandwidth is within 2o[...]

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Tektfgnl;. Date: 6/1190 Product: 494N494Ap Service Vot. 1 MANUAL CHANGB INFORMATION Change Reference: CA59A (revised) ManualPart No.070-5560-00 product GrOup: 2E o o C o O' o o o o o o o o o o rf a I o t o o o a o o o o I t t I I o o I C I a o I o I o The followlng is a revision of change Reference: c2ls90 datect slztgo. ln section 4 - PERFORM[...]

Change stepll as follows: 6. Check Reslduat FM [Within 7 kHz over 20 ms with the 1st LO unlocked (SPAN/DIV >200 kHz for band 1 and bands 5 rhrough 12 and SPAN/DIV >100 kHz for bands 2 rhrough 4)1. [Within (5 + N)Hz over 20 ms with rhe 1st LO locked (SPAN/DIV s200 kHz for band 1 and bands 5lhrough 12 and SPANiDIV <100 kHz tor bands 2 rhroug[...]

(2) Acrivare MARKER MENU pushbutton. (3) Select "7 - ENTER BANDWTDTH NUMBER" (4) Enter'60" with the keypad and terminate wilh "d8". (5) Activate BAND WIDTH mode pushbutton (<green_ sHIFT>BAND WTDTH). (6) From the information displayed on the CRT, record the 60 dB bandwidth in Tabte 4A. (7) Using the values in Tab[...]

RESOLUTION BANDWIDTH 3 MHz 1 MHz 6 dB BANDWIDTH LIMITS 60 dB Bandwidth RESOLUTION BANDWIDTH VERNCAL DISPLAY FREOUENCY SPAIVDIV 60 dB MEASURED BANDWIDTH Caleulated Shape Factor (60 dB/6 dB) SHAPE FACTOR SPECIFICATION 3 MHz 10 dB/ l MHz <7.5:1 1 MHz 10 dB/ 1 MHz <7.5:1 100 kHz 10 dB/ 100 kHz <7.5:1 '10 kHz t0 dB/ 5 kHz <7.5:1 1 kHz 1[...]

o o a a o t t - - o t o t0 I o a o o I o a C a o C I o t a I a I a o a t a o 'a a a o a I t Change step 12 as follows: 12. Check Calibrator Output (-20 dBm r0.g dB) a. Apply an external 100 MHz signal to lhe power meter through a 3 dB attenualor and a 50e iable. Set the generaror output level lor a reading ol -20 dBm on the power meter. Change[...]

o a o o a o ^ r J o I t I o o a o o o o I , o I o t o o o a a a I a I o I I o I t t o I t Figure 4.14. RF attenuator test equipment setup, Change step 14 as follows: 14. Check Frequency Response (Response about the midpoint between lwo exlremes measured with 10 dB of RF attenuation and peaking optimized in the applicable bands for each cenrer lregu[...]

Tercfgnix MANUAL cHANcE INFoRMAnoN CETvitTTEDT oEcEu.E^pE Date: l1_Sep_gl Product: See List . Change Reference: C1-991 Manual Part No.: See Lisl DESCRIPTION Prodrrct Group 2E o o o o o o ? I o a o t o o o o t t o o o O o o o o o a o J I a o o ) a o O a a O a o o Effective for Alt Sertal Numbers: 070-7556-00, Service Votume 1 070-5560-00, Service Vo[...]

Product: See Llst Date: 11 Ref. C1-991 Spectrum Analyzer Under Test Test equlpment,setup lor checklng I dB lnput compresslon polnt- b. Sefect lhe following settings for the specirum anatyzer: FBEQUENOY 103 MHz FREQUENCY SPAN/DIV 1 MHz RESOLUTION BANDWTDTH 1 MHz a o o o o o o I o o I I o O I a a a t o o I o o o O t o o o I o o a a I a I I o o I t o [...]

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