Frequency detector

摘要

A frequency detection technique includes generating first and second signals such that a frequency of the first signal is the same as a frequency of the second signal and such that the second signal is phase-shifted by a fixed amount with respect to the first signal. The technique further includes generating a third signal having a frequency that corresponds to an absolute value of a difference between the frequency of the first signal and an integer multiple of a frequency of the reference signal. The technique further includes generating a fourth signal having a frequency that corresponds to an absolute value of a difference between the frequency of the second signal and an integer multiple of the frequency of the reference signal. The technique further includes generating an fifth signal indicative of whether a phase relationship between the third and fourth signals is a leading phase relationship, a lagging phase relationship, or an in-phase relationship.

主权项

1. A device comprising:
a controlled oscillator having:
a control input,a first output, anda second output; a first mixer having:
a first input coupled to the first output of the controlled oscillator,a second input coupled to a reference signal, andan output; a second mixer having:
a first input coupled to the second output of the controlled oscillator,a second input coupled to the reference signal, andan output; and a phase detector having:
a first input coupled to the output of the first mixer,a second input coupled to the output of the second mixer, andan output.