Write Noise Rejection in an Optical Disk Drive
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
A non-linear filter eliminates noise which is generated by the reflection of a laser's write beam into the detectors of an optical disk drive's tracking and focusing servo systems. This noise appears as positive-going pulses. A circuit, as shown in the figure, is provided for each of these two servos. Diode 10 acts as a blocking gate for positive noise pulses which appear on input conductor 11. Capacitor 12 maintains the servo's error signal at the input of amplifier 13 during the short time period of the positive noise pulse.