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发明背景通信接收机中,可方便地采用包括变换器(例如单稳态多谐振荡器)的反馈电路来调整压控振荡器的频率,该变换器与振荡器的输出相耦合,把瞬时振荡频率转换成正比于重复率的直流脉冲序列。在指定的间隔期间,直流脉冲在(第一)贮存电容器中累积,同时,幅度随变换器变换系数变化的合成直流脉冲电压在差分放大器中与由电位器可变抽头取出的可调参考电压相组合。此合成的误差电位用来调整振荡器中的变容二极管,直至振荡器的输出频率响应于电位器的参考电压为止。
BACKGROUND OF THE INVENTION In communications receivers, feedback circuits including transducers (eg, monostable multivibrators) may be conveniently employed to adjust the frequency of the voltage controlled oscillator that is coupled to the output of the oscillator to provide instantaneous oscillation The frequency is converted into a DC pulse train proportional to the repetition rate. During a specified interval, a direct current pulse accumulates in the (first) storage capacitor while a composite direct current pulse voltage whose amplitude varies with the converter conversion factor is compared with an adjustable reference voltage phase in the differential amplifier taken out by the potentiometer variable tap combination. The resulting error potential is used to adjust the varactor in the oscillator until the oscillator's output frequency responds to the potentiometer's reference voltage.