AKG Acoustics WMS81 инструкция обслуживания

WMS61 & & WMS81 W ireless Microphone Systems[...]

3 Figure 1. Basic principles of FM transmission and reception Introduction: The art and science of wireless microphone design have progressed in recent years to a point where reliable and flexible performance can be taken for granted in even the most complex venues. What remains is for this level of performance to become available at competitive pr[...]

4 FM has been used for broadcast transmission of high quality audio since the mid-1950s, and its primary advantages are wide audio bandwidth and relative freedom from external electrical disturbances as compared to AM (amplitude modulation). The chief factors that determine the ultimate performance characteristics of an FM system are RF signal stre[...]

5 Noise Considerations: Monophonic FM broadcast transmission normally has a very high signal-to-noise ratio because of relatively high signal strength and high modulation index. In the wireless microphone area, where we are “crowding” many channels into a relatively small radiated bandwidth, the usable signal-to-noise ratio is about 60 dB — w[...]

Another technique for minimizing noise under marginal operating conditions is known as squelching . When the level of the incoming RF signal drops below a certain threshold, the system becomes prone to interference and may even pick up spurious signals. In older systems, the squelching threshold is a manual adjustment. The WMS 61 and 81 systems use[...]

7. Color coded rings (part number CCS-1): Included in the package is a set of color coded rings and matching rectangular snap-on color chips. These accessories help you keep track of which microphone corresponds to which receiver . For example, you can replace the black ring (the one you removed earlier) with the yellow ring, and snap its correspon[...]

3. Mute indicator: When this red status light is on, the system is muted, indicating low or no RF signal from the transmitter . The squelch action operates with a pilot tone from the transmitter and requires no manual adjustment at the receiver . It is the level of this signal that automatically mutes the system, preventing a rise in noise when the[...]

T rying Out the System: A T ypical Setup: Now that you have been introduced to the basic functions of the WMS 61 and 81 units, let’ s proceed with a typical setup. W e’ll choose the bodypack and use it with a clip-on lapel microphone such as the AKG Model CK 77 WR-L. (The L in the model number indicates that this model has the proper locking-ty[...]

Using Handheld T ransmitters: The same setup routine and precautions as we used for the bodypack apply here as well. Since a given handheld transmitter may be used by a number of speakers it is recommended that the initial checkout be made using the loudest of the speakers to ensure that the system can handle those maximum speech peaks. Softer talk[...]

11 Specifications PT61 bodypack transmitter: Audio bandwidth: 50 Hz to 20 kHz Modulation method: FM Radiated RF power: 10 mW Frequency stability: ±10 ppm Antenna: Flexible, quarter -wave wire Rated deviation: ±30 kHz Signal-to-noise ratio: T ypical 50 dB (A weighted) Input impedance: 220 kohms, 600 pF Audio input: Mini 3-pin XLR; 1400 mV for rate[...]

AKG Acoustics, U.S. • 1449 Donelson Pike • Nashville • TN 37217 • T el: (615) 360-0499 • Fax: (615) 360-0275 V isit our W eb Site at www .akgusa.com Specifications PT81 bodypack transmitter: Audio bandwidth: 50 Hz to 20 kHz Modulation method: FM Radiated RF power: 10 mW Frequency stability: ±10 ppm Antenna: Flexible, quarter -wave wire R[...]