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1) Focus Error Signal –> (A + C) - (B+C)
• In case of CD Disc
This signal is generated in RF AMP IC (IC301 : SSI3723) and controls the pick-up’s up and down to
focus on CD Disc.
2) Tracking Error Signal (3-Beam Method) –> F - E
• In case of CD Disc
This signal is generated in RF AMP IC (IC301 : SSI3723) and controls the pick-up’s left and right shift to
find the track on CD Disc.
3) RF Signal –> A+B+2C
• In case of CD Disc
This signal is converted to DATA signal in DSP IC (IC701 : CXD3030R).
2. Structure of the Photo Diode (CD)
Infrared laser
Pick-Up module
Photo Diode
Tracking
Focusing
(As seen from light
receiving side)
E
C
B
F
A