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1) Focus Error Signal –> (A+C) - (B+D)
• In case of DVD Disc
This signal is generated in RF AMP IC (IC301 : SSI3723) and controls the pick-up’s up and down to
focus on DVD Disc.
2) Tracking Error Signal (DPD Method) –> Differential phase of (A+C) and (B+D)
• In case of DVD 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 DVD Disc.
3) RF Signal –> A+B+C+D
• In case of DVD Disc
This signal is converted to DATA signal in DSP IC (IC201 : CXD1867R).
3. Structure of the Photo Diode (DVD)
(As seen from light
receiving side)
Red laser
Pick-Up module
Photo Diode
Tracking
Focusing
F
D
C
B
A
E