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CXD3068Q
§ 5-3. DC Offset Cancel [AVRG (Average) Measurement and Compensation] (See Fig. 5-3.)
The CXD3068Q can measure the average of RFDC, VC, FE and TE and compensate these signals using the
measurement results to control the servo effectively. This AVRG measurement and compensation is
necessary to initialize the CXD3068Q, and is able to cancel the DC offset.
AVRG measurement takes the levels applied to the VC, FE, RFDC and TE pins as the digital average of 256
samples, and then loads these values into each AVRG register.
The AVRG measurement commands are D15 (VCLM), D13 (FLM), D11 (RFLM) and D4 (TLM) of $38.
Measurement is on when the respective command is set to 1.
AVRG measurement requires approximately 2.9ms to 5.8ms (when MCK = 128Fs) after the command is received.
The completion of AVRG measurement operation can be monitored by the SENS pin. (See Timing Chart 5-2.)
Monitoring requires that the upper 8 bits of the command register are 38 (Hex).
Timing Chart 5-2.
<Measurement>
VC AVRG: The VC DC offset (VC AVRG) which is the center voltage for the system is measured and used to
compensate the FE, TE and SE signals.
FE AVRG: The FE DC offset (FE AVRG) is measured and used to compensate the FE and FZC signals.
TE AVRG: The TE DC offset (TE AVRG) is measured and used to compensate the TE and SE signals.
RF AVRG: The RF DC offset (RF AVRG) is measured and used to compensate the RFDC signal.
<Compensation>
RFLC:
(RF signal – RF AVRG) is input to the RF In register.
"00" is input when the RF signal is lower than RF AVRG.
TLC0:
(TE signal – VC AVRG) is input to the TRK In register.
TLC1:
(TE signal – TE AVRG) is input to the TRK In register.
VCLC:
(FE signal – VC AVRG) is input to the FCS In register.
FLC1:
(FE signal – FE AVRG) is input to the FCS In register.
FLC0:
(FE signal – FE AVRG) is input to the FZC register.
Two methods of canceling the DC offset are assumed for the CXD3068Q. These methods are shown in Figs.
5-3a and 5-3b.
An example of AVRG measurement and compensation commands is shown below.
$38 08 00
(RF AVRG measurement)
$38 20 00
(FE AVRG measurement)
$38 00 10
(TE AVRG measurement)
$38 14 0A
(Compensation on [RFLC, FLC0, FLC1, TLC1], corresponds to Fig. 5-3a.)
See the description of $38 for these commands.
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 ...
