System and method of noise correcting PLL frequency synthesizers

A noise-corrected phase-locked loop frequency synthesizer device comprising:

• a phase shifter configured to simultaneously accept a noise-uncorrected VCO frequency signal from a VCO, and noise reducing control signals from a noise detecting sensor, and output a noise-corrected VCO frequency signal;
• wherein said VCO is driven by a frequency divider, power splitter, first phase detector, first low pass filter, and first amplifier;
• and
• wherein said frequency divider is a programmable frequency divider with a programmable division coefficient N, said frequency divider configured to frequency divide said noise-uncorrected VCO frequency signal provided by said power splitter, and provide a frequency divided noise-uncorrected VCO frequency signal as input to said first phase detector;
• said first phase detector, first low pass filter, and said first amplifier configured to use said frequency divided noise-uncorrected VCO frequency signal, and a step-size reference frequency (F0), to drive said VCO to oscillate at a desired frequency that is a multiple of said step-sized reference frequency F0;
• wherein said noise detecting sensor is configured to compare a difference between at least a portion of said noise-corrected VCO frequency signal, and a lower noise reference at a same VCO frequency, and to use said difference to produce said noise correcting control signals for said phase shifter.

A method of noise-correcting a phase-locked loop frequency synthesizer, said method comprising:

• obtaining a phase locked loop frequency synthesizer comprising a VCO, a noise detecting sensor, and a phase shifter;
• using said phase shifter to simultaneously accept a noise-uncorrected VCO frequency signal from said VCO, and noise reducing control signals from said noise detecting sensor, and output a noise-corrected VCO frequency signal;
• further using said noise detecting sensor to compare a difference between at least a portion of said noise-corrected VCO frequency signal, and a lower noise reference signal at a same VCO frequency, and to use said difference to produce said noise correcting control signals for said phase shifter;
• and
• wherein said noise detecting sensor comprises a second phase detector, second low pass filter, second amplifier, and a plurality of series connected mixer stages;
• each said mixer stage comprising a mixer and a corresponding local oscillator circuit;
• using said plurality of series connected mixer stages and said second phase detector to compare said noise-corrected VCO frequency signal with a low-phase-noise reference frequency signal, and to produce phase noise difference signals;
• and
• using second low pass filter, said second amplifier and said phase noise difference signals to provide said noise reducing control signals to said phase shifter.