Automatic selection of an operating frequency in a low-gain broadband phase lock loop system

摘要

A broadband low-gain system for automatically frequency- locking a signal where the system uses digital and analog devices and techniques. The system includes a comparator, an up/down counter, a digital-to-analog converter, a decoder, a ring oscillator and a downcounter. The digital control signal is provided by the decoder and actuates one of a plurality of ring oscillator stages. The analog control signal is provided by the digital-to analog-converter and controls a fine- tune mechanism in the actuated stage. The system includes a master reset for clearing the counters.