Patent ID: 7670295

Claim:
A monitoring device for ambulatory and non-invasive physiological monitoring comprising: one or more inductive plethysmographic (IP) sensors for sensing changes in the size or shape of a selected portion of an ambulatory subject, where at least one such selected portion varies with the subject's respiration; and electronic unit sized to be carried by the subject and further comprising analog oscillator circuitry coupled to the IP sensors that generates analog signals with varying frequencies responsive to the changes sensed by the IP sensors, and digital counter circuitry coupled to the analog oscillator circuitry that receives the generated analog signals having varying frequencies, that counts complete cycles of the varying-frequency analog signals, that counts pulses of a digital clock signal occurring within the counted, complete cycles of the varying-frequency analog signals, and that outputs digital data representing the frequencies of the received, varying-frequency analog signals determined from the counts of digital-clock pulses and complete analog-signal cycles.