| 摘要 |
PURPOSE:To control appropriately the oscillation frequency at the time of transmission through a long transmission cable by frequency-modulating an oscillation frequency control signal of a partial oscillator at the side of a station selection circuit and supplying it to a frequency converter. CONSTITUTION:After a control signal 10 for controlling an oscillation frequency of a partial oscillator 4 at the side of a frequency converter 21 is modulated in terms of frequency, it is transmitted through a transmission cable 15. At this time, a control signal 28 subjected to frequency modulation hardly changes in terms of frequency itself when the cable 15 becomes longer and a voltage drop caused by its resistance loss becomes larger. Accordingly the signal 10 without fluctuation with respect to the signal 10 obtained at the side of a station selection circuit 22 can be always given to the oscillator 4 of the converter 21 after said signal is demodulated at the side of the converter 21. Thus a high frequency receiver can execute the stable selection action of a station irrespective of the length of the cable 15.
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