dCS 954 User Manual

Manual for Standard Software Version 1.5x

dCS Ltd

June 2000

 

 

P3D Behaviour

Mute on CRC Error

The P3D format includes error checking. Data is packed into AES3 subframes, and each subframe is checked for integrity before it is converted to analogue. In the event of an error being detected in a subframe, the unit mutes the entire subframe, and passes control over to a more complex control mechanism. This looks for a long run of error free subframes before it unmutes – v1.36 software looks for 150 msecs – and displays the message “CRC”. A single data error can cause quite long mutes.

The reason for the presence of this test is to detect input data of the wrong format, which will cause full scale white noise, and can potentially damage equipment. Statistically, the wrong format data can cause a few subframes to pass the error check occasionally, so muting a single subframe is quite suspect.

Bit Error Rates

The bit error rate (BER) for a dCS 904/dCS 954 running P3D is below 5x10-14, (0 errors over 64 hours). The same error rate is likely to hold for all AES3 type formats.

Manual part no: DOC136954 iss 2B1

Page 55

file 135954ma2b1.pdf available from website

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