– 138 –
CXD3068Q
§ 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 CXD3068Q, 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 set 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.
∗
Default values. These values can be set as desired by $C commands SFP0 to SFP3 and SRP0 to SRP3.
§ 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 CXD3068Q 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
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
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.
Summary of Contents for PV420S
Page 1: ...SERVICE MANUAL PV420S WWW BBK RU ...
Page 72: ... 69 CXD3068Q Block Diagram ...
Page 73: ... 70 CXD3068Q Pin Configuration ...
Page 122: ... 119 CXD3068Q Timing Chart 1 3 ...
Page 123: ... 120 CXD3068Q Timing Chart 1 4 ...
Page 124: ... 121 CXD3068Q Timing Chart 1 5 ...
Page 129: ... 126 CXD3068Q Timing Chart 2 1 ...
Page 130: ... 127 CXD3068Q Block Diagram 2 2 ...
Page 131: ... 128 CXD3068Q Timing Chart 2 3 ...
Page 134: ... 131 CXD3068Q Timing Chart 2 6 ...
Page 138: ... 135 CXD3068Q VCO C Mode Fig 3 3 Access Flow Chart Using VCO Control ...
Page 140: ... 137 CXD3068Q Block Diagram 4 1 ...
Page 143: ... 140 CXD3068Q Timing Chart 4 4 ...
Page 147: ... 144 CXD3068Q Fig 4 6 a Auto Focus Flow Chart Fig 4 6 b Auto Focus Timing Chart ...
Page 148: ... 145 CXD3068Q Fig 4 7 a 1 Track Jump Flow Chart Fig 4 7 b 1 Track Jump Timing Chart ...
Page 149: ... 146 CXD3068Q Fig 4 8 a 10 Track Jump Flow Chart Fig 4 8 b 10 Track Jump Timing Chart ...
Page 150: ... 147 CXD3068Q Fig 4 9 a 2N Track Jump Flow Chart Fig 4 9 b 2N Track Jump Timing Chart ...
Page 151: ... 148 CXD3068Q Fig 4 10 a Fine Search Flow Chart Fig 4 10 b Fine Search Timing Chart ...
Page 152: ... 149 CXD3068Q Fig 4 11 a M Track Move Flow Chart Fig 4 11 b M Track Move Timing Chart ...
Page 157: ... 154 CXD3068Q Fig 4 15 CD TEXT Data Timing Chart ...
Page 162: ... 159 CXD3068Q Fig 5 3a Fig 5 3b ...
Page 196: ... 193 CXD3068Q Description of Data Readout ...
Page 200: ... 197 CXD3068Q ...
Page 201: ... 198 CXD3068Q ...
Page 202: ... 199 CXD3068Q ...
Page 207: ... 204 CXD3068Q Package Outline Unit mm ...
Page 208: ...This data sheet has been made from recycled paper to help protect the environment 205 ...
