NGT—Technical description (2010)
76 NGT Transceiver System Technical Service Manual
Time division multiplex audio channels
The system audio uses TDM to produce seven channels of audio and one
synchronisation pulse to reference the channel timing.
The audio is sampled at a rate of 12.5 kHz by the TDM gates IC9/A and IC9/B. IC9/A
and IC9/B are driven by IC1.
The position of the audio channel varies depending on the requirements of the system. Its
position can be determined by attaching an oscilloscope at TP2.
Figure 19: Representation of the waveform as measured at TP2
IC11 on the Audio Interface PCB in the RF unit (drawing 04-03109), drives V3 and
IC6/A to generate the synchronisation pulse.
The TDM audio from TDM gates IC9/A and IC9/B is passed to the RF unit via SYS
AUDIO+/– on the CIB.
ALTERNATIVE TEXT
Drawing 04-03201, or
Drawing 04-03423
Sync pulse
Time
Audio (channel 3)
Channels
To Next Page
Loading...
Need help?
General
