| 摘要 |
PURPOSE:To decrease the detecting time of failure, by detecting the beat between a reference signal and a voltage-controlled oscillator signal. CONSTITUTION:An output of a reference signal oscillator is applied to an amplifier 2 and also applied to a phase comparator 4 after producing harmonics at a harmonic generator 3, to obtain an output signal multipled by N at a voltage-controlled oscillator VCO5. A reference signalis picked up from the amplifier 2 and it is multipled by N at a multiplier 9 and the beat with the output of the VCO5 is deteted at a mixer 10. If synchronism is disturbed, an output is made from the mixer 10,and the failure can be detected by processing this output at a capacitor diode detector 12a and a Schmitt trigger 12b. If no reference signal is present, this absence is detected at a detection circuit 13 to output a failure output. |
