Frequency Synthesis Tuning Systems With Automatic Offset Tuning

This paper describes a new closed-loop tuning system utilizing custom large scale integrated circuits to control the selection of the 82 U.S. television channels. The system is designed to minimize hardware but yet support multiple user features. No frequency adjustment or prealignment is needed for operation. A crystal frequency reference is continually used on each channel, but full compatibility with automatic fine tuning is maintained to cope with transmitters operating off FCC assigned frequencies. Channel selection is easily remoted and is either by digital keyboard or by up-down scan of a user selected list of channels stored in non-volatile digital memory. Channel number display is either on screen with time of day or off screen using a digital display.