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本发明是输入回路为电调谐的通信接收机,其调谐状态由加在接收机输入电路的调谐控制输入端的调谐电压决定。中频级与输入电路的输出端(混频级)相连。输出级所需的本振信号由具有信道选择装置的频率合成器提供,该合成器由加入粗调、细调控制环的压控振荡器组成。加到接收机输入回路的调谐电压是不同的,为调谐到所需的信道,这些电压按有关的调谐曲线改变,而该曲线则由信道选择装置的调整情况决定。
The present invention is a communications receiver whose input circuit is electrically tuned and whose tuning state is determined by the tuning voltage applied to the tuning control input of the receiver input circuit. The intermediate frequency stage is connected to the output of the input circuit (mixer stage). The LO signal required for the output stage is provided by a frequency synthesizer with channel selection means consisting of a voltage controlled oscillator that incorporates a coarse, fine control loop. The tuning voltage applied to the input loop of the receiver is different. To tune to the desired channel, these voltages are varied by the relevant tuning curve, which is determined by the adjustment of the channel selection means.