| 摘要 |
PURPOSE:To simplify the constitution, by simplifying the band of the band pass filter in matching with the band of the variable frequency oscillator VFO and by making unnecessary the selector switch selecting the pass band, through the provision of the first and second PLL. CONSTITUTION:When alternating signal in frequency f1 is fed to the mixing circuit 3 from VCO 21 and it is fed to the mixing circuit 22. Further, the alternating signal in frequency f2 is fed to the mixing circuit 22 from VCO 23. The signal from the mixing circuit 22 is fed to the band pass filter 24 and the alternating signal in frequency fm is picked up and this signal is fed to the phase comparison circuit 25. The alternating signal in frequency fv is fed to the circuit 25 from VFO 26. The comparison output in frequencies fv and fm is fed to the control terminal of VCO 21, constituting the first PLL 31. Further, the alternating signals of f2/N and f1/M are compared at the phase comparison circuit 28, the output is fed to VCO 23, constituting another PLL. |
