Electronic tuning unit for radio or TV receivers - uses active devices to adjust local oscillator by phase lock loop
Реферат: An electronic unit is used to provide phase-lock-loop tuning in radio and television receivers. It produces local oscillator signals from a reference frequency derived from a cristal oscillator. It has greater reliability and flexibility than the usual passive units. The unit has a series of preset resistors, a mono-stable multivibrator, and a programme selector to select the duration of the programming. There are also a local oscillator, counters, a switch and a phase comparator. The comparator produces an error signal representing the deviations in phase and frequency between the reference frequency signal and an output signal, nad also produces a signal for adjusting the local oscillator.
Phase locked loop television tuning system
Номер патента: CA1095194A. Автор: Charles M. Wine,John G.N. Henderson. Владелец: RCA Corp. Дата публикации: 1981-02-03.