dCS 904 User Manual

Manual for Software Version 1.5x and 1.36

dCS Ltd

June 2000

 

 

SDIF-2

PCM Format

The SDIF-2 interface is a 4 wire NRZ interface - so the DC level on each signal line may not be constant. It contains 20 bits of audio data and has a block structure of 256 stereo samples, rather than the 192 of AES/EBU. There are 8 bits of message per channel per sample - with a further 3 bits being used for an "illegal code" based sync code. Of the 8 bits per sample, the 8 in the first sample are reserved for system messaging, and the rest are for User messages.

The 4 wires are:

Ground return Left Channel Right Channel Word Clock

The sync codes can enable data recovery without the word clock, if necessary, but with the number of data formats in current operation, this method of locking is strongly discouraged. The waveforms below SDIF-2 waveforms (data and word clock) at 44.1 kS/s and 96 kS/s.

Figure 31 – SDIF-2 PCM format at 96 kS/s

Manual part no: DOC135904 iss 2B2

Page 50

135904ma2b2.pdf file available from website

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