CXD3003R datasheet(76/137 Pages) SONY

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CXD3003R

§4-2. Frame Sync Protection

• In normal-speed playback, a frame sync is recorded approximately every 136µs (7.35kHz). This signal is

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.

• In the CXD3003R, window protection and forward protection/backward protection have been adopted for

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 the 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.

§4-3. Error Correction

• In the CD format, one 8-bit data contains two error correction codes, C1 and C2. For C1 correction, the code

is created with 28-byte information and 4-byte C1 parity.

For C2 correction, the code is created with 24-byte information and 4-byte parity.

Both C1 and C2 are Reed Solomon codes with a minimum distance of 5.

• The CXD3003R uses refined super strategy to achieve double correction for C1 and quadruple correction for

C2.

• In addition, to prevent C2 miscorrection, a C1 pointer is attached to data after C1 correction according to the

C1 error status, the playback status of the EFM signal, and the operating status of the player.

• The correction status can be monitored externally. See Table 4-2.

• When the C2 pointer is high, the data in question was uncorrectable. Either the pre-value was held or an

average value interpolation was made for the data.

MNT3

No C1 errors;

C1 pointer reset

One C1 error corrected;

C1 pointer reset

—

No C1 errors;

C1 pointer set

One C1 error corrected;

C1 pointer set

Two C1 errors corrected;

C1 pointer set

C1 correction impossible;

C1 pointer set

No C2 errors;

C2 pointer reset

One C2 error corrected;

C2 pointer reset

Two C2 errors corrected;

C2 pointer reset

Three C2 errors corrected;

C2 pointer reset

Four C2 errors corrected;

C2 pointer reset

—

C2 correction impossible;

C1 pointer copy

C2 correction impossible;

C2 pointer set

MNT2

MNT1

MNT0

Description

Table 4-2.

CXD3003R Datasheet(PDF) 76 Page - Sony Corporation

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