Dolby Laboratories DP524 manuale d’uso

Model DP524 Two-Channel AC-2 / AC-3 Digital Audio Decoder Users' Manual MAIN[...]

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Users' Manual For Model DP524 A C-2 / A C-3 Tw o-Channel Digital Audio Decoder Dolby Laboratories Incorporated U.S.A. 100 Potrero Avenue, San Franc isco, CA 94103 Tel: 415-558- 0200; Fax: 415-863-1373 U.K. W ootton Bas sett, W iltshire SN4 8QJ Tel: 01793-842100; Fax : 01793-842101 DISCLAIMER OF WA RRANTIES: Equipm ent manufactured by Dolby Lab[...]

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TA BLE OF CONTENTS SECTION 1 Introduction 1.1 I ntroduction ................................................................................................... 1-1 1.3 Dolby AC-3 and AC-2 ................................................................................... 1-2 1.4 Data Rates, Sample Rates and Channels ................................[...]

SECTION 6 Interface Specif ication and Description 6.1 DP524 Interface Specifications ..................................................................... 6-1 AES/EBU Digital Audio Output, J101 ................................................... 6-1 S/PDI F Digital Audio Output, J102 ........................................................ 6-1 Enc[...]

SECTION 1 INTRODUCTION 1.1 Introduction The Dolby Model DP524 is a digital audio decoder unit supporting both Dolby AC- 2 and Dolby AC-3 digital audio coding algorithms. The unit supports up to two channels of audio. The data rates available are considerably lower than that required to convey conventional PCM data (between 40k and 384k bits/sec) ye[...]

1-2 1.2 Features • Automatic algorithm, data rate and sample rate selection • Dolby AC-3 audio coding algorithm from 40 kbps - 384 kbps • Mono, Dual-Mono or Stereo modes for AC-3 • Dolby AC-2 audio coding algorithm from 128 kbps - 384 kbps • Mono 2-channel modes for AC-2 • Analog outputs with 20-bit D/A converters • Digital outputs (A[...]

1-3 1.4 Data Rates, Sample Rates and Channels Possible AC-3 Data Rates, Sample Rates and Number of Channels Data Rate Sample rate Channels 40 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder 48 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder 56 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder 64 kbps 32kHz, 44.1kHz or 48kHz Set by Encoder 80 kbps 32kHz, 44.1kHz [...]

1-4 1.5 Regulatory Notices FCC This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and [...]

1-5 IEC NOTICES IMPORTANT SAFETY NOTICE This unit complies with the safety standard IEC65. To ensure safe operation and to guard against potential shock hazard or risk of fire, the following must be observed: GB o Ensure the voltage selector is set to the correct mains voltage for your supply . o Ensure fuses fitted are the correct rating and type [...]

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SECTION 2 APPLICATIONS The Dolby Model DP524 is suitable for a variety of point-to-point and point-to- multipoint digital transmission applications, including cable, telecommunications and satellite or terrestrial microwave links. The very high audio quality and low, spectrum-efficient data rates of the AC-2 and AC-3 coding process make them partic[...]

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SECTION 3 PRE-INSTALLATION 3.1 Unpacking Before proceeding further, be sure to inspect the outer carton for shipping damage. If there has been any penetration to the carton, be sure to inspect the unit for any physical damage in those areas. Several accessories have been provided in the packet provided with this manual. Please compare them with the[...]

3-2 OPEN THE DOOR ACTIVE FUSE CARRIER (LOWER) FUSE Check that the fuse in the active (lower) fuse carrier is of the correct rating. A spare fuse can be stored in the upper fuse carrier position. Snap the fuse compartment door closed. Internal Fuse The switching power supply contains a separate fuse. Most fault conditions should be protected by the [...]

3-3 front, rear, and each of the sides of the unit. The three black screws should be reserved for affixing at the front. Note The front panel is attached to the top cover by means of 4 screws also affixing the handles. These do not need to be removed. By grasping the front panel handles, gently pull the top cover/front panel assembly forward then a[...]

3-4 3.4.1 Jumpers for Encoded Data In & Timing (J103) Receive Timing J205 / Receive Data J206 [terminated] Termination resistors (150 ohms) are provided across the "RT" and "RD" inputs. These inputs are terminated in the default configuration, which should be appropriate for most applications. Certain situations may require [...]

3-5 Note Switch positions 5 and 6 take on two roles: • They set the Aux Data output baud rate when S101-2 is in the Normal position and S101-4 is in the Aux Data position • They set the Download baud rate when S101-2 is in the Download position. • Their positions are immaterial when S101-2 is in the Normal position and S101-4 is in the Comman[...]

3-6 3.5.3 Switch no. 3 - Digital Output Format Selection [up] Position this switch to corresponds to the type of digital output signal format. Refer to Section 4 for information regarding audio connections. Format S101-3 S/PDIF Down AES/EBU [Up] The switch setting selects how the digital bit stream is marked. S/PDIF is synonymous with "consume[...]

SECTION 4 INSTALLATION 4.1 Mounting The DP524 is designed for 19 inch rack mounting, but may be mounted in any plane and with any orientation. It occupies 1U (1 3/4") of space. When mounting the unit, ensure that there is air flow around it, and that it is not mounted directly above any equipment generating high amounts of heat. The unit will [...]

4-2 For optimum immunity to radio-frequency interference, cable shields must be connected to the shells of the XLR connectors, not to pin 1. In an installation where the source is unbalanced, avoid ground loops by using two conductor shielded cable exactly as for balanced circuits; in other words, ensure that the unbalancing (connecting the wire to[...]

4-3 Baud Rate S101-5 S101-6 0 Down Down 1200 Down Up 2400 Up Down 9600 Up Up Where is baud rate of the Encoder (generating the Aux data stream) is higher than the baud rate of the Decoder it is possible that data may be lost. 4.3.3 RS-422 (J106) The RS-422 connection is not supported in this product. 4.3.4 Parallel Status and Control (J104) It is p[...]

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SECTION 5 OPERATION Once the DP524 is installed and operational, no user-intervention is required. In normal operation, one of the Green LEDs will indicate the incoming sample rate (32kHz , 44.1 kHz or 48 kHz); the signal presence indicators will also illuminate if appropriate. 5.1 Front Panel Status Indicators Fault The Fault LED indicates power s[...]

5-2 5.2 Rear Panel Level Controls Each analog output connector has a level control adjacent to it. Each analog output is adjustable (at full scale) over a range of below 0dBu to greater than +24dBu. 5.3 Test Tone Level The operating level for the test tone generator of the Model DP524 is -18dB relative to full scale. This is useful when calibrating[...]

SECTION 6 INTERFA CE SPECIFICA TION A ND DESCRIPTION 6.1 DP524 Interface Specifications AES/E B U Digital Audio Output, J101 XL R-type connector, 5V p-p ty pical, 110 Ohms. Pin Connection 1 Digital sig nal ground 2 Digital Audio + 3 Digital Audio - S/PDIF D igital Audio Output, J102 BNC-ty pe connector, 0.5V p-p ty pical, 75 ohms. Encode d Data In [...]

6-2 Status / Control, J104 , 25-pin D-conne c tor: Pin Connection Comments 1 NC Do Not Connect 2 NC Do Not Connect 3 NC Do Not Connect 4 NC Do Not Connect 5 NC Do Not Connect 6 NC Do Not Connect 7 NC Do Not Connect 8 NC Do Not Connect 9 NC Do Not Connect 10 NC Do Not Connect 11 NC Do Not Connect 12 NC Do Not Connect 13 VREF Logic Level Reference (+[...]

6-3 6.2 RS-449 Interface Description 6.2.1 Functional D escr iption The Dolby Model DP524 provide a standard RS-449 interface in the type DT mode (data and timing signals only , no handshakes) throug h 37-pin male D-connectors. RS-449 is the mechanical specification for a balanced (differential) transmission sy stem meeting RS-422 and RS-423 electr[...]

6-4 6.2.3 B ac k-to-B ac k Te sting For purposes of testing the Model DP523 and Model DP524 in a back-to-back configuration, a special cable must be constructed. Note that a DTE-to-DTE connection is not supported by the RS-449 specification. A standard 37-wire cable cannot be used to interconnect the units. The special cable connects the TT outputs[...]

6-5 6.3 Serial Control I t is possible to command the DP524 via the RS-232 port, J 105 on the rear of the unit when the Command/Aux data switch (S101-4) is in the Up position. The communications protocol for command mode is fixed at 9600 baud, 1 stop bit, no parity . Note This port ca nnot be used sim ultaneously for exte rnal control and A uxiliar[...]

6-6 Com m and $18: Retur n Syste m Status $FB $20 $18 0 $FD The unit returns the following byte : B7 B6 B5 B4 B3 B2 B1 B0 0 Dr_lock Sr_lock Test 48kHz 44.1kHz 32kHz Mute Each bit is returned set if the associated signal is active. Dr_lock and Sr_lock are internal signals. Dr_lock i s active when the decoder has successfully locked to the incoming R[...]

6-7 This command will return $FF if the decoder is in Test Tone mode or if the decoder is in normal mode but does not have an input data clock that it can lock to. Otherwise the returned da ta is as follows: B7 B6 B5 B4 B3 B2 B1 B0 0000B R 3 B R 2 B R 1 B R 0 BR3 BR2 BR1 BR0 Bit Rate (total) 0001 40k bits/sec 0010 48k bits/sec 0011 56k bits/sec 010[...]

6-8 Com m and $42: Set Com pre ssion mode $FB $20 $42 data $FD Where data is as follows: B7 B6 B5 B4 B3 B2 B1 B0 0 00000 C 1 C 0 C0 and C1 are defined as follows: C1 C0 Comment 0 0 Custom mode, no digital dialog normalization 0 1 Custom mode, digital dialog normalization 1 0 L ine Out Mode 1 1 RF mode MAIN[...]

SECTION 7 DP524 SPECIFICATION Specifications 1 Italics = nomenclature for panel markings, switch labels, jumpers, LEDs, etc. All inputs and outputs are TTL compatible unless otherwise stated. Frequency Response Lower limit: 20 Hz. Upper limit varies from 8 to 20 kHz depending on algorithm. Tolerance ± 0.3 dB. Distortion 2 AC-2 Less than 0.1 % at 1[...]

7-2 Digital Audio Outputs AES/EBU, 3-pin XLR-type, male, balanced , 110 ohms ±5%, 5V pp nominal. S/PDIF, BNC female connector, unbalanced, 75 ohms ±5%, 0.5V pp nominal. Data Output / Command Input RS232, Male 9-pin D connector. RS-422, Female 25-pin D connector. These connectors may be used to load software upgrades into the unit, allow serial co[...]

7-3 General Power Requirements 90-260 VAC, 50-60 Hz, 24VA Dimensions and Weight 1- ¾ x 19 x 11- ¾ inches (4.45 x 48.26 x 29.8 cm), 8.5 pounds (3.9 kg), approx. Emissions Complies with the limits for a Class A digital device, pursuant to Part 15 of the FCC Rules. Environmental Requirements Temperature Operating : 0 o C to 50 o C, natural convectio[...]

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