| 摘要 |
PURPOSE:To secure the output of the oscillation signal which can correspond in a high accuracy to the input signal through a simple constitution by extracting the voltage difference between the sample holding circuits from the subtractor and then adding the voltage difference with the initial set value for supply to the voltage control oscillator. CONSTITUTION:The output of voltage control oscillator 20 to be controlled and the input singal to be identified are supplied alternately to frequency discrimination circuit 15 and with switching, and the output is led to sample holding circuit 16 and 17. Thus the difference of the holding voltage between circuit 16 and 17 shows the difference between the input signal frequency and the oscillation freqfency then, and this voltage difference is extracted from subtractor 18 to be added 19 with the prescribed initial voltage level and then supplied to oscillator 20. This oscillation frequency is made to approximate to the input carrier frequency to oabtain an agreement. In this way, the oscillation signal corresponding in a high accuracy to the input signal can be delivered through a simple constitution. |
