PROCEDURE AND RECOMMENDATION FOR REDUCTING THE RACE OF AN OSCILLATOR BY PREPARING THE RACE

摘要

A circuit for reducing phase noise in a transmitted radio signal includes a first phase-locked loop circuit including a first controlled oscillator generating a first output signal at a first desired frequency, and a first phase comparator developing a first phase error signal to control the first controlled oscillator, the first error signal representative of phase differences between the first output signal and the first desired frequency. A second phase-locked loop circuit includes a second controlled oscillator generating a second output signal at a desired frequency of transmission related to the first desired frequency, and a second phase comparator developing a second phase error signal representative of phase differences between the first output signal and the desired frequency of transmission. A summer combines the first and second error signals to control the second controlled oscillator to thereby reduce, or cancel, phase noise generated by the first controlled oscillator in the second output signal transmitted as a radio signal at the desired frequency of transmission.