Microwave Data Systems MDS 4310, Установка, эксплуатация и техническое обслуживание на месте

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MDS 05-2415A01, Rev. A J-1
APPENDIX J
AUDIO PROCESSING MODULE
Optional System Equipment
Assembly P/N: 03-2301A01
INTRODUCTION
The Audio Processing Module is used in applications where no method of keying the remote
transceiver is provided by the RTU or modem. The assembly senses the presence of an audio
tone on the transmit audio line and, in turn, keys the transmitter. This function is typically
called a VOX function. When installed in the MDS 4310 Transceiver, the Audio Processing
Module is mounted in the Option 1 position on the main transceiver board. See Figure J-3.
Figure J-1 and J-2 show the component layouts for the Audio Processing Modules. The
boards contain an array of switches to configure the assembly for a variety of interface
requirements. The assemblies consist several circuits—a VOX circuit (discussed above), a
transmit audio pre-emphasis circuit, receive audio de-emphasis circuit and limiter circuitry.
These circuits may be turned on and off independently using the configuration switches.
The automatic level control (ALC) circuitry is continuously enabled and provides the correct
audio level for the transceiver. The audio input level should be between -30 and 0 dBm.
OPTION 1—
Modem PC Assembly or
Audio Processing Module
OPTION 2—
Remote Maintenance Module
or Diagnostic & Loopback Module
TRANSCEIVER
PC BOARD
Figure J-1. Audio Processing Module Installation Diagram
SPECIFICATIONS
Power Requirements: +10 Vdc @ 1 mA standby; 8 mA activated
Key-up Time: Less than 2 milliseconds; 0.25 ms typical
Release Time: Less than 10 milliseconds; 5 ms typical