Christopher N Day

US Patent:

41379071, Feb 6, 1979

Filed:

Dec 27, 1976

Appl. No.:

5/754387

Inventors:

William D. Jansen - Palo Alto CA
Jerry D. Haney - Sunnyvale CA
Christopher C. Day - Newtonville MA
Stephen A. Schneeberger - West Hartford CT

Assignee:

American Optical Corporation - Southbridge MA

International Classification:

A61B 502

US Classification:

128 205M

Abstract:

Improved method and apparatus for identifying and quantizing a substantially periodic, steeply rising wavefront of a signal in the possible presence of low amplitude interference. A time derivative of at least the steep wavefront is obtained. The derivative is then integrated over a predetermined interval in each of successive repetitions of the steep wavefront, the interval being that during which the derivative exceeds a reference level. A threshold value is established, preferably dynamically, to verify or validate that when the derivative exceeds the reference level it indeed represents the steeply rising wavefront. The integrated derivative is recognized as the quantized value of the steeply rising wavefront only if such verification occurs. The invention is suited to oscillometric determination of systolic pressure in a patient, where measurement of signal amplitude is preferably achieved by integrating the time derivative of the systolic rise wavefront.