| 摘要 |
PURPOSE:To ensure the automatic frequency control over a wide band by eliminating the elements giving the band limitation from the pulse generator circuit and the switching circuit. CONSTITUTION:Voltage control oscillator VCO10 generates frequency fV which varies in response to the control signal sent from digital frequency discriminator 15. In addition to VCO10, crystal oscillator 11 is provided to oscillates the high frequency signal of reference frequency fX. Using the output of oscillator 11 as the input, the repetitive frequency identical to frequency fX is obtained, and the pulse row containing higher harmonic component nfX of frequency fX is generated from pulse generator circuit 12. This pulse row of circuit 12 is applied to switching circuit 13 to give switching to output frequency fV of VCO10, and then differential frequency component nfX-fV is delivered to the output of circuit 13. The output of circuit 13 is applied to discriminator 15, and the frequency discrimination is given to component nfX-fV based on oscillation frequency fO of crystal oscillator 16. Thus component nfX-fV is supplied in the form of the control signal of VCO10. |
