Pioneer YPM-MG2196ZF Service Manual page 56

YPM-MG2196ZF
9) MIRR (mirror) circuit
MIRR signal shows ON and OFF track information. The
signal is output from Pin 31.
The status of MIRR signal is as follows:
Laser beam ON track: MIRR = "L"
Laser beam OFF track: MIRR = "H"
The signal is used in the brake circuit mentioned later.
10) 3T OUT circuit
The system detects flickering of RF signal when distur-
bance is input to the focus servo loop, and outputs the
difference of phase between FE signal and RF-level
fluctuation signal from Pin 30. The resulting signal is
obtained through L.P.F. with a fc of 40 Hz. This signal is
used for automatic adjustment of FE bias.
56
UPC2572GS
Detection
RFO
RFIN AGC Peak
4
Bottom
Fig.6 MIRR Circuit
RFO
OFF TRACK
PEAK HOLD
A
BOTTOM HOLD
B
C
Z
MIRROR
1
0
True MIRR
Fig. 7 MIRR Circuit
UPC2572GS
Differential
4 AGC
RFIN
rectification
C1.3T
3T LEVEL ENVELOPE
7
C108
DETECTOR
0.027µF
H.P.F
C2.3T
8
C109
Phase detection
100pF
10kΩ
10kΩ
FEY
C113
10nF
Fig. 8 3T OUT Circuit
A
(Peak) – (Bottom)
C
COMP
B
DC
shift
Z
1.5V
Dirt, etc.
Ø
False MIRR caused by dirt
1kΩ
L.P.F
3T-OUT
120kΩ
Phase
3T detection
30
comparison
8
C117
0.033µF
FE signal
29
MIRR
31