US Patent 11909406 Ring oscillator phase-locked loop with digital phase noise suppression

An electronic device may include wireless circuitry having mixer circuitry configured to receive an oscillator signal from phase-locked loop circuitry. The phase-locked loop circuitry may include a digital or analog phase-locked loop having a first frequency divider, a ring oscillator, and an auxiliary phase noise cancellation loop coupled to the ring oscillator. The auxiliary phase noise cancellation loop may include at least a time-to-digital converter, a second frequency divider, an amplifier, and a bandpass filter configured to reject thermal and quantization noise associated with the time-to-digital converter. The first frequency divider may have a first division ratio, whereas the second frequency divider may have a second division ratio that is less than the first division ratio to provide faster phase noise correction.