Systems and methods for determining respiration information using phase locked loop

摘要

A patient monitoring system may receive a physiological signal such as a photoplethysmograph (PPG) signal that exhibits frequency and amplitude modulation based on respiration. A phase locked loop may generate a frequency demodulated signal and an amplitude demodulated signal from the PPG signal. An autocorrelation sequence may be generated for each of the frequency demodulated signal and the amplitude demodulated signal. The autocorrelation sequences may be combined and respiration information may be determined based on the combined autocorrelation sequence.

主权项

1. A method for determining respiration information, the method comprising:
receiving a photoplethysmograph (PPG) signal; generating, using processing equipment, an oscillator signal; adjusting, using the processing equipment, the oscillator signal based on a phase difference between the PPG signal and the oscillator signal; generating, using the processing equipment, a demodulated signal based on the PPG signal and the oscillator signal, wherein the demodulated signal comprises a frequency demodulated signal; shifting, using the processing equipment, a phase of the oscillator signal, generating, using the processing equipment, an amplitude demodulated signal based on the PPG signal and the phase shifted oscillator signal and determining, using the processing equipment, the respiration information based on the amplitude demodulated signal and the frequency demodulated signal.