Kenwood DP-3010 Service Manual page 14

DP-3010
CIRCUIT DESCRIPTION
Setting of R5 ~ R8 for Focus Gain Adjustment
The following simply explains the operations for Focus
Gain Adjustment and the method for setting R5 ~ R8
1) Focus Gain Adjustment
®@ As soon as Focus Gain Adjustment is started, FEL1 and
FEL2 of TC9201BF become VAEF.
@ During Focus Gain Adjustment the internal Focus Error
Signal of TC9201BF is in Peak Data Hold Mode. The
Peak Data achieved is set to the internal resister.
e As soon as Focus Gain Adjustment is complete. the
Peak Data achieved in TC9201BF is decoded. FEL1 and
FEL2 are then set to either one of the conditions shown
in Diagram 5-4. (Refer to TC9201BF Technical Informa-
tion for details)
be
Setting Method of R5 ~ R8
® The peak values of the Focus Error Signal within the
Pick-up dispersion during VREF, the compared range of
R5 ~ R8 of pins FEL1 and FEL2 are set as shown in Dia-
gram 5-4 (R6 is self setting).
@ Each Focus Error Signai within the range is set with R6
—~ R8 to about 0.4 Vp-o (about 0.8 Vp-p) peak vaiue at
the FEI pin (Oniy R6 > R7). The attenuate amount of
the Attenuator in Diagram 5-3 is as follows
VEFI 1 =
~~ VEFO R5 RS , RS
R6 * a7 RB
KE —
t+
Note: The peak value of the Focus Error Signal of the FEO
pin is set sc that the previous stage gain is more
than 0.4 Vp-c within the Pick-up dispersion range
RS
b b d
mu} i FEL2
VREF
Diagram 5-3 Focus Gain Adjustment Construction
FEI Peak Value (Vp-o}
(X VreF)
0.26
0.156
0.125
0.0937
Diagram 5-4 Pin FEL1 and FEL2 Conditions
DP-3010
CIRCUIT DESCRIPTION
@ Tracking Error AMP
© Focus Error Output AMP
Diagram 5-6 is constructed of the Triangle Tooth Wave
Producing Circuit, the FSO AMP used as the phase com-
pensator for Focus signals and the control circuit that
switches the Focus Servo Signal and the Focus Search
Focus Servo Signat
RT (TE) = 2RNFS (RNFS = RO = VR3+ R10)
TE output
Tracking Error Signal
TEO (F-E)
Tracking Error AMP (TE}
Diagram 5-5 Tracking Error AMP Construction
Phase Compensation Circuit
Focus Servo Signal
Focus Error Output AMP (FE}
Switch Control Signal
VREF
Diagram 5-6 Focus Error Output AMP Construction 25