Revision 2.2
Page 21
Coding of preamble
The data to be transmitted is formed into bursts of data. A 64-bit preamble is added to the
beginning of each burst. The remainder of the burst is then the data payload. The preamble
occupies 16 bits in each of 4 sub-frames. The preamble is considered to be four 16-bit words
designated as Pa, Pb, Pc, Pd. The contents of these four words are specified in Table 1. When
placed into a sub-frame, the MSB of a 16-bit preamble word is placed into time slot 27, and the
LSB is placed into time slot 12. The combination of Pa and Pb form a 32-bit sync code. This
allows a receiver to find the preamble with a very small probability of mis-detection.
Table 1 Preamble Words
Preamble word
Contents
Pa
16 bit sync word 1 = 0xF872
Pb
16 bit sync word 2 = 0x4E1F
Pc
16 bit burst_info value.
Pd
16 bit length_code (unsigned integer), equal to
the number of data bits in the following data burst
32-bit mode
The 4 preamble words are contained in 2 sequential frames. The frame beginning the data
burst contains preamble word Pa in the Ch1 sub-frame, and Pb in the Ch2 sub-frame.
The next
frame contains Pc in Ch1 and Pd in Ch2.
16-bit mode
The 4 preamble words are contained in 4 sequential sub-frames of the individual channel (Ch1
or Ch2) being employed to convey the DTS data stream. The sub-frame (of the channel being
used) beginning the data burst contains preamble word Pa, the next sub-frame (of the channel)
in the burst contains Pb, etc.
burst_info
The 16-bit burst_info value contains information about the data which will be found in the burst.
The contents of burst_info is specified in Table 2.
Bit 15 of burst_info is considered the MSB.
Table 2 burst_info
Bit(s)
Value
0-4
Data_type
(5-bit unsigned integer = 0-31)
5-6
Reserved (shall be set to ‘00’)
7
Error_flag 1 indicates data burst may contain
errors, 0 indicates data may be valid
8-12
Data_type_dependent
13-15
Data_stream_number
Summary of Contents for CAE-4
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