Servo Block; Focus Servo - Harman Kardon FL8550 Service Manual

FL8550

SERVO BLOCK

1. FOCUS SERVO

When the defect signal is detected, the focus servo Loop is isolated. At this time, the focus servo error
output is outputted through low pass filter formed by connecting a capacitor (0.1µF) between the built-in
470KΩ resistor and FDFCT Pin (Pin58). Accordingly, the focus error output is held as just before error
value during the defect.
The peak frequency of the focus phase compensation is at about 1.2KHz when the resistor connected to
PFSET(Pin7) is 510KΩ. It is inversely proportional to the resistor connected to the Pin 7.
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