Automatic Loop gain Control System of DAD Player’s tracking servo

The Digital Audio Disc and Player will be put on the market in '82 Autumn, for expectation consumer products. In 3 spots pick up System, which is composed of main-spot for reading recorded signal and focusing servo, and of 2 side-spots for getting track following signal, lens actuator noise appears in playback. For audio products, the noise is fatal defect. So, it is important, to decrease the noise. The detector sensitivity of track following signal level is deviated by the disc characteristics of reflection ratio, modulation, and crosstalk etc. However, DAD Player needs the stable pick up servo system for any disc. We developed the Automatic Loop gain Control System which solved those problems.