VOLTAGE CONTROL OSCILLATOR, PHASE SYNCHRONIZING CIRCUIT AND SIGNAL PROCESSING CIRCUIT

摘要

PURPOSE: Disclosed is an inexpensive voltage control oscillator by means of simplifying a configuration and easily attaining realization in an integrated circuit by positively feeding back a pulse signal obtained by means of binarizing the output signal of a delay amount variable filter to the input side of the filter by a desired level. CONSTITUTION: A quaternary butter-worth low-pass filter(LPF)(7) is used as the delay amount variable filter. In the LPF(7), a cut-off frequency is changed in accordance with a control signal from a control input node(5), a delay time is changed with it, an input signal is delayed and the signal is output. A voltage comparing circuit(comparator)(8) for binarizing the input signal and outputting the pulse signal with desired amplitude is connected to a positive feedback loop circuit at the output side of the LPF(7). Then loop connection is executed to positively feed back the output pulse signal to the LPF(7).