Frequency synthesizer and method thereof
AssigneeIndustrial Technology Research Institute
InventorFeng-Hsu Chung
Life of this patent
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Abstract
A frequency synthesizer is provided. The frequency synthesizer includes a jitter-cleaning phase-locked loop, a fractional phase-locked loop, a mixer, and a radio-frequency phase-locked loop. The jitter-cleaning phase-locked loop receives a reference clock and a mixed signal, and suppresses a jitter of the reference clock to generate a first oscillating signal based on the reference clock and the mixed signal. The fractional phase-locked loop receives the reference clock and generates a second oscillating signal based on the reference clock. The mixer mixes the first oscillating signal and the second oscillating signal to generate the mixed signal. The radio-frequency phase-locked loop receives the first oscillating signal and generates an output signal based on the first oscillating signal.
Claims20
A frequency synthesizer, comprising:
- a jitter-cleaning phase-locked loop, comprising a voltage-controlled oscillator, configured to receive a reference clock and a mixed signal, and suppress a jitter of the reference clock to generate a first oscillating signal based on the reference clock and the mixed signal, wherein the voltage-controlled oscillator is a voltage-controlled crystal oscillator;
- a fractional phase-locked loop, comprising another voltage-controlled oscillator, configured to receive the reference clock, and generate a second oscillating signal based on the reference clock, wherein the another voltage-controlled oscillator is another voltage-controlled crystal oscillator;
- a mixer, coupled to the jitter-cleaning phase-locked loop and the fractional phase-locked loop, configured to mix the first oscillating signal and the second oscillating signal to generate the mixed signal;
- and
- a radio-frequency phase-locked loop, coupled to the jitter-cleaning phase-locked loop, configured to receive the first oscillating signal, and generate an output signal based on the first oscillating signal.
A frequency synthesizing method used by a frequency synthesizer, wherein the frequency synthesizer comprises a jitter-cleaning phase-locked loop, a fractional phase-locked loop, a mixer, and a radio-frequency phase-locked loop, the method comprising:
- suppressing, by the jitter-cleaning phase-locked loop, a jitter of a reference clock to generate a first oscillating signal based on the reference clock and a mixed signal, wherein the jitter-cleaning phase-locked loop comprises a voltage-controlled oscillator, and the voltage-controlled oscillator is a voltage-controlled crystal oscillator;
- generating, by the fractional phase-locked loop, a second oscillating signal based on the reference clock, wherein the fractional phase-locked loop comprises another voltage-controlled oscillator, and the another voltage-controlled oscillator is another voltage-controlled crystal oscillator;
- mixing, by the mixer, the first oscillating signal and the second oscillating signal to generate the mixed signal;
- and
- generating, by the radio-frequency phase-locked loop, an output signal based on the first oscillating signal.
Dependencies are inferred from the claim text.