| 摘要 |
PROBLEM TO BE SOLVED: To suppress waveform distortion of a chirp signal in chirp signal generation in a conventional phase synchronization circuit.SOLUTION: A phase synchronization circuit includes: a voltage controlled oscillator for changing the output signal frequency with a control voltage; a frequency divider for dividing an output signal of the voltage controlled oscillator; a phase frequency comparator for comparing a phase of a reference signal and a phase of an output signal divided by the frequency divider, and outputting a voltage corresponding to the phase difference; a differential charge pump circuit for converting a voltage outputted from the phase frequency comparator into differential current, and outputting the differential current; a first switch for switching polarity of the differential current outputted from the differential charge pump circuit; and a differential loop filter for converting the differential current outputted by the first switch into a differential voltage and outputting the differential voltage as the control voltage of the voltage controlled oscillator. The voltage controlled oscillator generates a chirp signal according to the differential voltage outputted from the differential loop filter.SELECTED DRAWING: Figure 1 |
