| 摘要 |
PURPOSE: To provide a dual-mode phase detector which has a phase-only mode and a phase-and-frequency mode and the same gain in both modes. CONSTITUTION: A dual-mode phase detector incorporates a detection and feedback circuit 20 for detecting phase and frequency differences and generating first and second feedback signals for controlling a voltage-controlled oscillator 18. A mode switch circuit 24 switches the operation mode of the circuit 24 between a phase-only mode and a frequency mode. A programmable delay circuit 22 delays a signal received from the switch circuit 24 and supplies the delayed signal to the circuit 20. A frequency divider divides the frequency of the output signal of the oscillator 18 by a prescribed number and supplies an output signal having a frequency of a rational number to the circuit 20. Finally, an optionally selected edge detecting circuit 28 converts a prescribed data signal into a format which can be recognized in the circuit. |
