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CXD3068Q
§ 5-10. DFCT Countermeasure Circuit
The DFCT countermeasure circuit maintains the directionality of the servo so that the servo does not
become easily dislocated due to scratches or defects on discs.
Specifically, these operations are achieved by detecting scratches and defects with the DFCT signal
generation circuit, and when DFCT goes high, applying the low frequency component of the error signal
before DFCT went high to the FCS and TRK servo filter inputs. (See Fig. 5-13.)
In addition, these operations are activated by the default. They can be disabled by setting D7 (DFSW) of
$38 to 1.
Fig. 5-13.
§ 5-11. Anti-Shock Circuit
When vibrations occur in the CD player, this circuit forces the TRK filter to switch to gain-up mode so that the
servo does not become easily dislocated. This circuit is for systems which require vibration countermeasures.
Concretely, vibrations are detected using an internal anti-shock filter and comparator circuit, and the gain is
increased. (See Fig. 5-14.)
The comparator level is fixed to 1/16 of the maximum comparator input amplitude. However, the comparator
level is practically variable by adjusting the value of the anti-shock filter output coefficient K35.
This function can be turned on and off by D19 of $1 when the brake circuit (described hereafter) is off. (See
Table 5-17.)
This circuit can also support an external vibration detection circuit, and can set the TRK servo filter to gain-up
mode by inputting high level to the ATSK pin.
When the upper 4 bits of the command register are 1 (Hex), vibration detection can be monitored from the
SENS pin.
It also can be monitored from the ATSK pin by setting the ASOT command of $3F to 0.
Fig. 5-14.
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 ...
