DIGITAL TUNING SYSTEM FOR A VARACTOR TUNER EMPLOYING FEEDBACK MEANS FOR IMPROVED TUNING ACCURACY

摘要

ELIAS COHENDIGITAL TUNING SYSTEM FOR A VARACTORTUNER EMPLOYING FEEDBACK MEANS FORIMPROVED TUNING ACCURACYABSTRACT OF THE DISCLOSUREA tuning system for use in a communicationsreceiver having a varactor tuner includes an alterable,non-volatile memory having a plurality of memory locations,each of which is capable of storing a data word represen-tative of a tunable frequency, a signal selector andmeans for selecting a memory location in accordance withthe actuation of the signal selector and for sensing thedata word at the selected location. A feedback loop isutilized to improve the accuracy of the tuner. The loopincludes circuitry capable of sensing the frequency towhich the tuner is tuned, and generating a second dataword representative of the sensed frequency. The datawords are compared and an error signal in accordance withthe difference therebetween is generated. The tunedfrequency of the tuner is varied in accordance with theerror signal. Capability to vary the stored data word atthe selected location is provided to permit changes in thefine tuning setting.