IMPROVED SERVO SYSTEM, RECORD CARRIER AND PLAYBACK DEVICE

摘要

To improve the performance of a servo system, used for tracking a track on a record carrier, the bandwidth of the servo system must be adjusted. Instead of injecting a signal into the servo system to allow adjustment of the bandwidth, the track position modulation of the record carrier is used. The tracked position modulation comprises two signals of which the signal with the lower frequency has a higher amplitude than the signal with the higher frequency. After the reduction by the servo system the second signal is used as a reference and optimal adjustment of the bandwidth can be achieved.