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PHOTO DIODE STRUCTURE OF THE PICK-UP
1.
Focus Error Signal => (A+C)-(B+D)
(Control the Pick-up’s up and down to focus on the Disc)
2.
Tracking Error Signal => (E-F)
(Control the Pick-up’s left and right shift to find the track on the Disc)
3.
RF Signal => (A+B+C’)=(A+B+C+D)
(RF Signal is converted to Data Signal in DSP IC (IC501))
Three signals (Focus Error Signal, Tracking Error Signal and RF Siganl) above are I-V converted and
amplified at the IC102, and than are transmitted to DSP & SSP IC (IC501) to generate the Servo Control
Signal and Data Signal.
E
F
A
B
C'
Laser spot
Red laser
Pick-Up module
Tracking
Focusing
* C ’=C+D
