Abstract: An improved method and apparatus for non-invasive determination of blood pressure is disclosed. The oscillometric technique is employed, wherein a valve representative of the blood pressure is derived from a signal representative of the pressure oscillations in a cuff, where the value is derived for a plurality of cuff pressures, and where the cuff pressure corresponding to the maximum of the values derived from the pressure oscillations is taken to be the mean arterial pressure. The instant method uses as the value the complementary oscillation index which is defined to be the area bounded by a line connecting successive peaks in the signal and the signal beneath the line, divided by the time between peaks. Apparatus employing both digital and analog circuitry is employed.

Abstract: A telemetry receiver for demodulating subcarrier frequencies is disclosed. The flexibility of the receiver permits it to decode signals from a wide variety of transmitters. In the preferred embodiment, a biomedical digital telemetry subcarrier demodulator employs microprocessor control of a variable bandpass filter and cycle counter. The bandpass of the filter is set by the microprocessor to pass frequencies at and around the center frequency of the desired subcarrier frequency. The counter is preset for the desired number of cycles. In operation, the desired subcarrier frequency is passed by the filter, through a signal shaper, and to the counter. Upon receiving the first cycle, the counter activates a timer, which measure the period of the predetermined number of cycles. The desired signal is the percentage deviation of the subcarrier period from the average subcarrier period.