Abstract: A method of detecting subject respiratory motion and non-respiratory motion includes: transmitting a transmitted signal toward a subject, the transmitted signal being an ultrasound wave, the transmitted signal reflecting off the subject to produce a reflected signal; receiving the reflected signal and converting a form of the reflected signal from ultrasound wave to electrical; comparing the reflected signal to at least a first reference signal to determine at least a first reference phase signal indicative of a first phase difference between the first reference signal and the reflected signal, the at least a first reference signal being associated with the transmitted signal; and analyzing the first reference phase signal for respiratory motion of the subject and non-respiratory motion, the non-respiratory motion including at least one of non-respiratory motion of the subject or motion of an entity other than the subject.

Abstract: A method of detecting subject respiratory motion and non-respiratory motion includes: transmitting a transmitted signal toward a subject, the transmitted signal being an ultrasound wave, the transmitted signal reflecting off the subject to produce a reflected signal; receiving the reflected signal and converting a form of the reflected signal from ultrasound wave to electrical; comparing the reflected signal to at least a first reference signal to determine at least a first reference phase signal indicative of a first phase difference between the first reference signal and the reflected signal, the at least a first reference signal being associated with the transmitted signal; and analyzing the first reference phase signal for respiratory motion of the subject and non-respiratory motion, the non-respiratory motion including at least one of non-respiratory motion of the subject or motion of an entity other than the subject.