LC89057W-VF4A-E
10.7 IEC61937, DTS-CD/LD Detection Flag Output
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A function to output IEC61937 and DTS-CD/LD detection flags for Non-PCM data is provided.
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When the UNPCM of non-PCM signal output setting is selected through the INT output contents setting, an interrupt
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signal is output from INT detecting an IEC61937 or DTS-CD/LD sync signal. Reading output register from this
information can see details of Non-PCM signal.
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•
•
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When bit 1 of channel status is non-PCM data ("1"), the IEC61937 sync signal is detected and output. If bit 1 is PCM
data, the IEC61937 sync signal is not output.
DTS-CD/LD sync signal detection is done based on the sync pattern and the base frequency. DTS-ES data detection is
output when the DTS5.1 channel sync signal is detected and the DTS-ES sync pattern is verified.
The IEC61937 and DTS-CD/LD detection flags are cleared when fs have changed or a PLL lock error or data error
has occurred.
Since the DTS sync signal is provided within the audio data, digital data with the same code as the DTS sync signal
may exist in rare cases for regular CD/LD records that are not recorded in the DTS format. Protection using the sync
pattern or base frequency is provided so that such data is not misinterpreted as DTS-CD/LD detection flags. The
detection sequence is shown below.
Input data
NO
Bit 1detection
Bit 1=1
YES
NO
NO
PaPb
detection
DTS-CD/LD SYNC
detection
YES
YES
Frame counter
start
Frame counter
reset
Frame counter
start
Frame counter
reset
Frame count
512,1024,2048,4096
SYNC detection
PaPb detection
during 4096
frames
NO
NO
YES
YES
IEC61937 flag
not valid
INT lowered
DTS-CD/LD flag
not valid
INT lowered
IEC61937 flag OK
INT lowered
DTS-CD/LD flag OK
INT lowered
*
Frame count hold
x2 count detection
expansion
PaPb detection
during 4096
frames
NO
YES
* Depending on the frame count,
· the subsequent detection count
· is expanded up to ×2.
Frame count
512,1024,2048,4096
SYNC detection
NO
*
IEC61937 data hold
· Periodic fluctuation is supported.
YES
1st count
2nd count
512
1024
2048
4096
512 or 1024
1024 or 2048
2048 or 4096
4096
⇒
⇒
⇒
⇒
DTS-CD/LD
data hold
Figure 10.16 IEC61937 and DTS-CD/LD Data Detection Sequence
No.7202-31/59
SANYO [ SANYO SEMICON DEVICE ]
