| 摘要 |
PURPOSE:To facilitate a fine tuning by simplifying the preset operation without a variable resistor to generate a tuning voltage and a programmable variable frequency divider in the electronic channel selection unit used in a receiving unit. CONSTITUTION:VHF and UHF tuner 12 having a tuning variable reactance element, reference oscillator 16 which generates signals of a prescribed frequency, and gate circuit 15 which gates the local oscillation output of tuner 12 on the basis of the output of oscillator 16 are provided, and further, channel memory 20 which reads out a channel frequency code by the designation of channel designation switch 1 is provided. Comparison counter 19 which compares the frequency code read from memory 20 and the output of gate circuit 15 with each other is provided, and further, station counter 6 which changes a voltage code on a basis of the output of counter 19 or the output of fine-tuning pulse generator 9, and the voltage code from counter 6 is converted to a tuning voltage of tuner 12 by D/A converter 11 and is supplied to the reactance element. |
