Patent ID: 9706945
Date: 2017-07-18
CPC Classifications: A61B

Claim:
1. A method for deriving a signal quality metric, comprising: acquiring an impedance respiration signal; generating a series of sets of windowed data from the impedance respiration signal, wherein each window of data comprises data points acquired over a specified duration and is offset from a preceding window by a fixed interval; filtering the impedance respiration signal through at least an in-band filter to generate an in-band filtered signal; for each window of in-band filtered signals, generating a respective power spectral density; determining whether the respective power spectral density for a current window is noisy or not noisy; if the respective power spectral density for the current window is not noisy, updating a previous power spectral density template based on the respective power spectral density for the current window to generate a current power spectral density template, wherein the respective power spectral density for the current window is weighted greater than the previous power spectral density template when generating the current power spectral density; if the respective power spectral density for the current window is noisy, not updating the previous power spectral density template; identifying at least one peak and the corresponding frequencies and powers associated with the identified peaks within the current power spectral density template; and determining a respiration rate based on the at least one identified peak.