User Guide

PAMS
Technical Documentation
RAE-3
8. Troubleshooting
Page 8 – 62
Issue 1 06/01
2.18 COBBA PCM Interface Troubleshooting
PCM interface transfers digital audio data. Problems in this interface result in
missing or flawed audio in either or both in uplink and downlink directions. If
Wintesla shows errors in ”COBBA serial interface”, PCM interface is faulty.
Check PCMDClk signal at J309:
520 kHz square wave
50 per cent duty cycle
Rising and falling edges about 3 to 5 ns
Inactive state low?
NOYES
OK?
N200 faulty
Check PCMSClk at J306
short pulse, rate 8.000kHz
1.52 per cent duty cycle
Rise and fall times about 3 to 5 ns
Inactive state low?
NOYES
OK?
N200 faulty
Check PCMRx Data signal at J308
Activity during call and voice recording
If mic picks up sound, higher states at the cycle start
Rise and fall times about 3 to 5 ns
Signal idle state High with some 13MHz noise?
NOYES
OK?
N200 faulty
Check PCMTx data signal at J307
Activity during call
Rise and fall times about 4 to 7 ns
Idle statle low?
NO
OK?
N200 faulty
Ref. fig. 49
Ref. fig. 48
Ref. fig. 50
Ref. fig. 51
Figure 47.
There is no traffic in PCM interface without a call or audio play (voice recorder,
video player, etc). These signals can be measured with a call, which generates