Signal Detection Of The P/U - LG BP50NB40 Service Manual

3. Signal detection of the P/U

1) Focus Error Signal ==> (A+C)-(B+D)
This signal is generated in DSP IC(IC101 : MT1959H) controls the pick-up's up and down to focus on
Disc.
2) Tracking Error Signal (DPP Method) ==> {(A+D)-(B+C)}- k x {(EF
This signal is generated in DSP IC(IC101 : MT1959H) controls the pick-up's left and right shift to find to
track on Disc.
3) RF Signal ==> (A+B+C+D)
This signal is converted to DATA signal in DSP IC(IC101 : MT1959H)
Tp/2
Main
Sub2
Offset
TE
Pick-Up module
Track Center
Tp
Photo Diode
Sub1
D, C
A, B
F4, F3
F1, F2
k[(EF1+EF4) - (EF2+EF3)]
(A+D) - (B+C)
(A+D) - (B+C) - k[(EF1+EF4) - (EF2+EF3)]
25
Infrared Iaser
Focusing
Tracking
+EF )-(EF +EF )}
1 4 2 3
E4, E3
E1, E2
EF1=E1+F1
EF2=E2+F2
EF3=E3+F3
EF4=E4+F4