| 摘要 |
PURPOSE:To maintain a high-speed frequency switching response and to ensure a stable working in the steady state through lowering the feedback gain, by inserting a simple variable gain circuit into the frequency compounding device to secure a high feedback gain under the nonphase synchronous state. CONSTITUTION:The frequency phase comparator 2 compares both the frequency and the phase between the reference signal fR supplied from the reference frequency oscillator 1 and the output signal obtained by giving a step-down to the output frequency of fO of voltage controlling oscillator 4 through the variable frequency step- down device 5. Thus an error signal is obtained to be supplied to next variable gain device 6. In case the pulse of the error signal in the device 6 has a wide waveform, the higher harmonic component is excluded through a low pass filter of the resistance 7 and capacitor 8 to obtain a signal having a reduced distortion. This signal is transmitted to the output via a diode, while the signal having a small duration has a reduced waveform amplitude and does not pass through the diode to be delivered via the resistance 11. Thus the voltage control oscillator 4 is controlled by the output of the device 6 via the low pass filter 3. When the error signal has a large pulse duration due to a switching of frequency or the like, the feedback gain is increased to accelerate the response speed. |
