| 摘要 |
PURPOSE:To obtain a so-called synthesizer receiver applying the frequency synthesizing technique in that the channel selection is performed by setting the oscillation frequency of the local oscillator to the prescribed value via the output of the reference oscillator. CONSTITUTION:Intermediate-frequency amplifier 2, FM demodulator 3, muting circuit 4 and stereo demodulation part 5 are connected to front end 1. Thus the right and left signals are obtained at the output terminals 5R and 5L respectively. The local oscillation frequency of front end 1 undergoes the frequency multiplication via mixer 6 and 1/4-divider 8 and is then compared with the output given from reference oscillator 11 through 1/N-divider 9 at frequency phase comparator 10. And this output is fed back to the local oscillator to carry out the channel selection. In addition, the circuit is provided to vary the division ratio of divider 9 and then detect the fact that the receivable broadcast station has been received, along with the memory which can memorize the contents of the channel selection counter. |
