| 摘要 |
PROBLEM TO BE SOLVED: To provide a PLL circuit which is hardly affected by noise which differentiates all loops and is suitable for integration, even in a voltage- controlled oscillator using a variable capacitance diode, etc., from among its resonance circuits of the voltage-controlled oscillator constituting the PLL circuit. SOLUTION: The output signal of a phase comparator 13 is averaged by means of a low-pass filter 15, after the DC values of differential signal are converted by means of a dc conversion circuit 14, so that the differential voltage between the differential signals necessarily becomes a positive or negative value and inputted to the controlled voltage terminals 1 and 2 of a voltage- controlled oscillator 11. Since the DC values are converted, the control voltage of the oscillator 11 is differentiated, and a PLL circuit in which all loops are differentiated can be realized. |
