Digital tuning system for a varactor tuner employing feedback means for improved tuning accuracy

摘要

A tuning system for use in a communications receiver having a varactor tuner includes an alterable, non-volatile memory having a plurality of memory locations, each of which is capable of storing a first digital number representative of a tunable frequency. A signal selector actuates circuitry for selecting a memory location which senses a first digital number at the selected location. A feedback circuit senses the frequency to which the tuner is tuned and generates a second digital number, which represents the sensed frequency. The digital numbers are compared and an error signal generated in accordance with the difference. The tuned frequency of the tuner is varied in accordance with the error signal. The stored number at the selected location may be varied to provide a change in the fine tuning setting.