– 62 –
CXA2550M/N
Description of Functions
RF Amplifier
The photodiode current input to the input pins (PD1, PD2) are current-to-voltage (I-V) converted by the
equivalent resistance of 58k
Ω
at PD I-V amplifiers, respectively. The signal is added by the RF summing
amplifier and then the I-V converted output voltage of the photodiode (A + B + C + D) is output to RFO pin.
This pin is used check the eye pattern.
The frequency response of the RF output signal can be equalized by adding the capacitance (Cp) to RFI pin.
The low frequency component of the RFO output voltage is as follows;
V
RFO
= –2.75
×
(V
A
+ V
B
)
= 159.5k
Ω ×
(iPD1 + iPD2)
Focus Error Amplifier
The difference between the RF I-V amplifier output VA and VB is obtained and the I-V converted voltage of the
photodiode (A + C – B – D) is output.
The FE output voltage (low frequency) is as follows;
V
FE
= 5.4
×
(V
A
– V
B
)
= (iPD2 – iPD1)
×
315k
Ω
GND
33k
4
15
I-V
PD1
58k
2k
VA
PD1 IV AMP
33k
I-V
PD2
58k
2k
VB
PD2 IV AMP
5
RF SUMMING AMP
5.5k
14
RFM
RFO
Cp
V
CC
12
13
174k
24p
164k
32k
32k
87k
24p
V
EE
47k
FE
FE BIAS
VB
VA
– (B + D)
– (A + C)
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 ...
