cxd2548r Sony Electronics, cxd2548r Datasheet - Page 57

• Manufacturer Part Number: cxd2548r
• Description: Cd Digital Signal Processor With Built-in Digital Servo And Dac
• Manufacturer: Sony Electronics

3-2. Frame Sync Protection
• In normal-speed playback, a frame sync is recorded approximately every 136µs (7.35kHz). This signal is
• In the CXD2548R, window protection and forward protection/backward protection have been adopted for
3-3. Error Correction
• In the CD format, one 8-bit data contains two error correction codes, C1 and C2. For C1 correction, the code
• The CXD2548R's SEC strategy uses powerful frame sync protection and C1 and C2 error correction to
• The correction status can be monitored externally.
• When the C2 pointer is high, the data in question was uncorrectable. Either the pre-value was held or an
used as a reference to recognize the data within a frame. Conversely, if the frame sync cannot be
recognized, the data is processed as error data because the data cannot be recognized. As a result,
recognizing the frame sync properly is extremely important for improving playability.
frame sync protection. These functions achieve very powerful frame sync protection. There are two window
widths: one for cases where a rotational disturbance affects the player and the other for cases where there is
no rotational disturbance (WSEL = 0/1). In addition, the forward protection counter is fixed to 13, and the
backward protection counter to 3. Concretely, when the frame sync is being played back normally and then
cannot be detected due to scratches, a maximum of 13 frames are inserted. If frame sync cannot be detected
for 13 frames or more, the window opens to resynchronize the frame sync.
In addition, immediately after the window opens and the resynchronization is executed, if a proper frame
sync cannot be detected within 3 frames, the window opens immediately.
is creased with 28-byte information and 4-byte C1 parity.
For C2 correction, the code is created with 24-byte information and 4-byte C2 parity.
Both C1 and C2 are Reed Solomon codes with a minimum distance of 5.
achieve high playability.
See Table 3-1.
average value interpolation was made for the data.
MNT3
0
0
0
1
1
1
MNT1
0
0
1
0
0
1
MNT0
Table 3-1.
0
1
1
0
1
1
No C1 errors
One C1 error corrected
C1 correction impossible
No C2 errors
One C2 error corrected
C2 correction impossible
Description
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CXD2548R