Abstract: A method and apparatus for preserving audio and video presentation synchronization during the splicing operation by selectively deleting, if necessary, an audio/video access unit to avoid overlapping of audio/video frames in the spliced output stream.

Abstract: In a capacitance distance sensor apparatus in a focus servo loop for an optical disc playback and record system, stable high servo loop gain and small closed-loop error correction signals are achieved despite surface variations of the disc by compensating for the periodic error command signals generated by the surface variations.A comb filter is provided in the loop tuned to major error component frequencies. The comb filter is formed of a plurality of parallel, bandpass filters that are tuned to frequencies substantially corresponding to the disc rotation frequency and several harmonics thereof. In the distance sensor servo focus control loop, the loop gain can be maintained at a high value to achieve proper beam focus within 0.5 micron (0.5.times.10.sup.-6 meters) for disc surface amplitude variation of three mils (0.0075 centimeters) peak-to-peak.

Abstract: A peak detector circuit is provided for detecting the maximum excursions of an amplitude varying signal. The circuit includes a network comprising a capacitor serially coupled to a charging impedance and having a time constant suitable for responding to the maximum excursions of the amplitude varying signal. A semiconductor means has an input terminal for receiving the amplitude varying signal and an output terminal coupled to the charging impedance for charging the capacitor toward the maximum excursions of the amplitude varying signal. The semiconductor means exhibits an impedance which is subject to increase with a decrease in current drawn therethrough.