CM6571 Datasheet, PDF (39/63 Pages) C-Media Electronics – USB 2.0 full speed-compliant

8.7 SPDIF control description
8.7.1 SPDIF frame description
 Audio format: linear 16-bit default, up to 24-bit expandable
 Audio sampling frequencies (Fs):
 44.1kHz from CD
 48kHz from DAT
 32kHz from DSR
 One-way communication: from a transmitter to a receiver
 Control information:
 V (validity) bit: indicates if audio sample is valid
 U (user) bit: user free coding, i.e. running time song and track number
 C (channel status) bit: emphasis, sampling rate and copy permit
 P (parity) bit: error detection bit to check for good reception
 Coding format: biphase mark except the headers (preambles), for sync purposes
 Bandwidth occupation: 100kHz up to 6Mhz (no DC)
 Signal bitrate is 2.8Mhz (Fs=44.1kHz), 2Mhz (Fs=32kHz) and 3.1Mhz (Fs=48kHz)
CM6571
USB Audio Sound Chip
Clock
Data Signal
10011010010
Biphase Mark
Signal
1011001010110100110100
SPDIF Biphase Mark Signal Diagram
Preamble
Cell Order
Cell Order
(last cell "0")
(last cell "1")
------------------------------------------------------
"B"
11101000
00010111
"M"
11100010
00011101
"W"
11100100
00011011
Preamble B: Marks a word containing data for channel A (left) at the start of the data-block.
Preamble M: Marks a word with data for channel A that is not at the start of the data-block.
Preamble W: Marks a word containing data for channel B (right, for stereo). When using more than two channels,
this could also be any other channel (except for A).
Revised: Nov. 2012
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