– 166 –
CXD3068Q
§ 5-12. Brake Circuit
Immediately after a long distance track jump it tends to be hard for the actuator to settle and for the servo to
turn on.
The brake circuit prevents these phenomenon.
In principle, the brake circuit uses the tracking drive as a brake by cutting the unnecessary portions utilizing the
180° offset in the RF envelope and tracking error phase relationship which occurs when the actuator traverses
the track in the radial direction from the inner track to the outer track and vice versa. (See Figs. 5-15 and 5-16.)
Concretely, this operation is achieved by masking the tracking drive using the TRKCNCL signal generated by
loading the MIRR signal at the edge of the TZC (Tracking Zero Cross) signal.
The brake circuit can be turned on and off by D18 of $1. (See Fig. 5-17.)
In addition, the low frequency for the tracking drive after masking can be boosted. (SFBK1, 2 of $34B)
Fig. 5-15.
Fig. 5-16.
Register
name
Command
D23 to D20
D19 to D16
1 0
∗ ∗
0
∗ ∗ ∗
∗
1
∗ ∗
∗
0
∗ ∗
∗ ∗
0
∗
∗ ∗
1
∗
∗ ∗ ∗
1
∗ ∗ ∗
0
ANTI SHOCK ON
ANTI SHOCK OFF
BRAKE ON
BRAKE OFF
TRACKING GAIN NORMAL
TRACKING GAIN UP
TRACKING GAIN UP FILTER SELECT 1
TRACKING GAIN UP FILTER SELECT 2
0 0 0 1
TRACKING
CONTROL
1
Table 5-17.
∗
: Don't care
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 ...
