CXA1782 SONY [Sony Corporation], CXA1782 Datasheet - Page 15

• Manufacturer Part Number: CXA1782
• Description: RF Signal Processing Servo Amplifier for CD players
• Manufacturer: SONY [Sony Corporation]

Tracking Error Amplifier
The photo diode currents input to E and F pins are each current-voltage converted by the E I-V and F I-V
amplifiers.
The CXA1782 tracking block has built-in circuits for balance and gain adjustments to enable software-based
automatic adjustment.
The balance adjustment is performed by varying the combined resistance value of the T-configured feedback
resistance at E I-V AMP.
Vary the value of R
For the gain adjustment, the TE AMP output is resistance-divided by the gain adjustment switches (TOG1 to
TOG3), and it is output at Pin 42.
These balance and gain adjustment switches are controlled through software commands.
F I-V AMP feedback resistance = R
E I-V AMP feedback resistance = R
1k
3.3µ
E3
iF
iE
in the formula above by using the balance adjustment switches (BAL1 to BAL3).
F
E
39
38
VC
VC
F I-V AMP
E I-V AMP
260k
260k
R
R
12p
12p
F1
E1
VF
VE
40
VC
EI
F1
E1
+ R
+ R
– 15 –
VC
F2
E2
30k
30k
+
+
R
R
F1
E1
VC
R
R
TE AMP
x R
x R
F3
E3
96k
F2
E2
= 403kΩ
VC
42
TEO
CXA1782CQ/CR