Midband phase noise reducer for PLLS
AssigneeRaytheon Company
InventorsTuan M. Tong, William K. Mcgehee, Michael R. Patrizi
Life of this patent
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Abstract
A signal generator. A voltage controlled oscillator generates a signal that is fed to a comb generator, e.g., a nonlinear transmission line. A tone, from among a comb of tones at the output of the comb generator, is selected by a bandpass filter, its frequency is divided, e.g., by a direct digital synthesizer, and the result is compared, e.g., by a phase and frequency detector that receives a reference signal at its other input. The output of the phase and frequency detector is fed back, e.g., through a lowpass filter, to the voltage controlled oscillator.
Claims28
A signal generator, comprising:
- a voltage controlled oscillator;
- a comb generator having an input operatively coupled to an output of the voltage controlled oscillator, the comb generator being a nonlinear transmission line;
- a first filter having an input connected to an output of the comb generator;
- a first frequency divider having an input connected to an output of, and configured to receive an output signal from, the first filter;
- and
- a signal comparator having a feedback input connected to an output of the first frequency divider and a reference input, the signal comparator having a first output and being configured to generate at the first output a signal that is a measure of:
- a phase difference;
- or
- a frequency difference between a signal at the feedback input and a signal at the reference input,
- the first output of the signal comparator being operatively coupled to a control input of the voltage controlled oscillator.
A signal generator, comprising:
- a voltage controlled oscillator;
- a comb generator having an input operatively coupled to an output of the voltage controlled oscillator;
- a first filter having an input connected to an output of the comb generator;
- a first frequency divider having an input connected to an output of, and configured to receive an output signal from, the first filter;
- and
- a signal comparator having a feedback input connected to an output of the first frequency divider and a reference input, the signal comparator having a first output and being configured to generate at the first output a signal that is a measure of:
- a phase difference;
- or
- a frequency difference
- between a signal at the feedback input and a signal at the reference input,
- the first output of the signal comparator being operatively coupled to a control input of the voltage controlled oscillator,
- wherein the first frequency divider is a direct digital synthesizer.
A signal generator, comprising:
- a voltage controlled oscillator;
- a comb generator having an input operatively coupled to an output of the voltage controlled oscillator;
- a first filter having an input connected to an output of the comb generator;
- a first frequency divider having an input connected to an output of, and configured to receive an output signal from, the first filter;
- a signal comparator having a feedback input connected to an output of the first frequency divider and a reference input, the signal comparator having a first output and being configured to generate at the first output a signal that is a measure of:
- a phase difference;
- or
- a frequency difference
- between a signal at the feedback input and a signal at the reference input,
- the first output of the signal comparator being operatively coupled to a control input of the voltage controlled oscillator;
- and
- a second frequency divider connected between the voltage controlled oscillator and the comb generator.
Dependencies are inferred from the claim text.