User manual

dCS 950 / 952 User Manual Manual for Software Version 6.2x
dCS Ltd 22
nd
May 2000
Manual part no: DOC0029526B1 Page 39 Document No: OS-MA-D0002-952.6B1
Contact dCS on + 44 1799 531 999 email to: [e-mail]
(inside the UK replace + 44 with 0) web site: www.dcsltd.co.uk
SDIF-2
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 (Ch1)
Right Channel (Ch2)
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 show SDIF-2 waveforms (data
and Word Clock) at 44.1 kS/s and 96 kS/s.
Figure 19 – SDIF-2 format at 96 kS/s