US 12,316,332 B2 · Digital clean up oscillator

Abstract

A digital clean-up oscillator and associated method are provided for cleaning jitter from a noisy clock signal, comprising receiving a reference clock oscillator signal and the noisy clock signal to be cleaned: measuring the frequency of the reference clock signal in the time domain of the noisy clock signal: filtering any frequency variations from the measured frequency of the reference clock signal on timescales shorter than a phase change interval Tau_clean over which jitter in the noisy clock signal is to be cleaned; generating a phase increment signal DDS_pinc based on the measured and filtered frequency of the reference clock signal: clocking the phase increment signal DDS_pinc with the reference clock signal for generating an output digital phase ramp signal φ_DDS(t) that tracks the frequency of the noisy clock signal with phase wander removed on timescales less than the phase change interval Tau_clean; and converting the output digital phase ramp signal φ_DDS(t) to an output jitter-cleaned time domain clock signal frequency locked to the noisy clock signal.

Claims13

Dependent claims

A digital clean-up oscillator, comprising:

a reference oscillator for generating a high-stability reference clock signal;
a precision digital frequency tracker for receiving the reference clock signal and a noisy clock signal to be cleaned, and in response measuring the frequency of the reference clock signal in the time domain of the noisy clock signal;
a low pass filter for removing any frequency variations from the measured frequency of the reference clock signal on timescales shorter than a phase change interval over which jitter in the clock signal is to be cleaned;
a phase increment calculator for generating a phase increment signal based on the frequency of the reference clock signal measured in the precision digital frequency tracker and filtered by the low pass filter;
a direct digital synthesizer for clocking the phase increment signal with the reference clock signal for generating an output digital phase ramp signal that tracks the frequency of the noisy clock signal with phase wander removed on timescales less than the phase change interval;
and
a digital phase to clock converter for converting the digital phase ramp signal to an output jitter-cleaned time domain clock signal frequency locked to the noisy clock signal.

4 more elements

A method of cleaning jitter from a noisy clock signal, comprising:

receiving a reference clock oscillator signal and the noisy clock signal to be cleaned;
measuring the frequency of the reference clock signal in the time domain of the noisy clock signal;
filtering any frequency variations from the measured frequency of the reference clock signal on timescales shorter than a phase change interval Tau_clean over which jitter in the noisy clock signal is to be cleaned;
generating a phase increment signal DDS_pinc based on the measured and filtered frequency of the reference clock signal;
clocking the phase increment signal DDS_pinc with the reference clock signal for generating an output digital phase ramp signal φ_DDS (t) that tracks the frequency of the noisy clock signal with phase wander removed on timescales less than the phase change interval Tau_clean;
and
converting the output digital phase ramp signal φ_DDS (t) to an output jitter-cleaned time domain clock signal frequency locked to the noisy clock signal.

4 more elements

Dependencies are inferred from the claim text.

Digital clean up oscillator

Life of this patent

Digital clean up oscillator

Life of this patent

Abstract

Claims13