| 摘要 |
A phase synchronous circuit includes a comparing unit for comparing an output of a low-pass filter with a reference voltage which causes the central frequency of a voltage-controlled oscillator to be set as well as generating a compared output voltage by integrating a compared output current, a frequency oscillator for generating a frequency signal to frequency-modulate an output of the voltage-controlled oscillator and a switching unit for, in the presence of an input signal to the phase synchronous circuit, causing the compared output voltage to provide negative-feedback to a second control terminal of the voltage-controlled oscillator, whereas, in the absence of the input signal, to the phase synchronous circuit, causing the frequency signal to be input to the second control terminal of the voltage-controlled oscillator.
|
