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dCS 974 User Manual Manual for Software Version 1.0x
dCS Ltd May 2001
Manual part no: DOC1241121A1
Page 70
Document No: OS-MA-A0124-112.1A1
Contact
dCS
on + 44 1799 531 999 email to: more@dcsltd.co.uk
(inside the UK replace + 44 with 0) web site: www.dcsltd.co.uk
dCS 974
T
ECHNICAL
I
NFORMATION
Digital Data Formats Supported
dCS 974 provides nine digital data i/o formats:
AES/EBU (often referred to as AES3) for PCM operation
Dual AES (part of the AES3 spec) for PCM operation
Quad AES (part of the AES3 spec) for PCM operation
SDIF-2 for PCM operation
SDIF-2 for DSD operation
SDIF-3 for DSD operation
DSD Quad for DSD operation
SPDIF (electrical) for PCM operation
SPDIF (optical) for PCM operation
For all formats, the incoming Channel Status and User messages are
discarded
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. The unit allows the AES/EBU and SPDIF output Channel Status
bits to be edited.
The enhanced AES/EBU interface is fully implemented. Each channel has its
own parity and data validity bit, as well as User and Channel Status messages.
Cyclic Redundancy Counts (CRC's) are generated from the Channel Status
message.
The Dual AES interface allows an 88.2 or 96kS/s 24 bit signal to be coded as
two standard 44.1 or 48kS/s 24 bit AES data streams, recorded as four tracks
on a recorder with standard capacity, replayed and decoded back into a single
data stream. Operation of the Dual AES interface at double speed allows the
unit to input or output 2 wire 176.4 or 192 kS/s 24 bit data, and convert to and
from this.
The Quad AES interface allows an 176.4 or 192kS/s 24 bit Dual AES data
stream to be coded as four standard 44.1 or 48kS/s 24 bit AES data streams,
recorded as eight tracks on a recorder with standard capacity. It may be
replayed and converted into a Dual AES stream, a single wire format or DSD.
SDIF-2 PCM message bits are internally set to zero, with the exception of the
block code, which is implemented.
The SPDIF interface has no CRC's - as per definition. Data formats for both
SPDIF electrical and SPDIF optical are identical.
DSD has, at the time of writing, no messaging structure. Contact dCS for more
details. Data formats use either the SDIF-2 system (two data channels and
third clock channel), the SDIF-3 format (two data channels with embedded
clock) or the DSD Quad format (four AES3 style data streams).
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At present we do this because there is no standard on what to do with the excess or shortage of bits that is
created by a sample rate change. If this causes you a problem, call us – we can probably do something else,
if we are clear what that ought to be.