Preset tuning apparatus using floating gate type field effect device

Abstract

A preset tuning apparatus adapted for selecting a preset channel among a plurality of channels, comprising a tuner including a tuning circuit including a voltage controlled variable capacitance diode, a manually adjustable tuning voltage generator for providing a tuning voltage to the voltage controlled variable capacitance diode, a non-volatile analog storage including a plurality of floating gate type field effect memory devices, a band selection switch, a preset selection switch, a preset memory switch, addressing circuits coupled to the band selection and preset selection switches for addressing a corresponding one of the plurality of memory devices, an erase/write/read voltage generator, and a mode control coupled to the erase/write/read voltage generator and responsive to the band selection, preset selection and preset memory switches for alternately and repetitively writing and reading the analog value in the addressed memory device until the data corresponding to the tuning voltage of the tuning voltage generator is written in the memory device in the write and read modes and for reading thereafter the data in the memory device for providing the same as a tuning voltage to the voltage controlled variable capacitance diode in the preset mode, whereby the preset selection is achieved based on the data as written in and read out from the addressed memory device. Preferably, the data concerning the tuning voltage is divided into a rough tuning voltage and a fine tuning voltage, which are separately stored in separate memory devices. Preferably, the read tuning voltage is once stored in a buffer memory and the tuning voltage in the buffer memory is corrected responsive to an automatic frequency control signal.