Patent ID: 7764987
Filing Date: 2010-07-27
Classification: A61B,A61N

Abstract:
1. A signal processing apparatus, said apparatus comprising: an input stage configured of receive a time-varying physiological signal having a morphology that changes over time, and configured of operate on said time-varying physiological signal to generate an evaluable time-varying signal having an alternating polarity; an evaluation stage operatively connected to said input stage, said evaluation stage configured to respond to a reference moment in time and configured to receive said evaluable time-varying signal; and an output stage operatively connected to said evaluation stage, wherein said evaluation stage comprises a zero-crossing detector, a curve point detector, and a maximum/minimum detector, wherein said zero crossing detector is configured to detect zero crossings in at least one signal segment of said evaluable time-varying signal and determining a time of occurrence of said zero crossings with respect to said reference moment in time, and wherein said curve point detector is configured to detect curve points between neighboring zero crossings in said at least one signal segment of said evaluable time-varying signal, said curve points either representing magnitudes of said evaluable time-varying signal or inflection points of said evaluable time-varying signal, or both, between said neighboring zero crossings, and said curve point detector being further configured to determine a time of occurrence of said curve points with respect to said reference moment in time and an amplitude of said evaluable time-varying signal at said curve points, and wherein said maximum/minimum detector is configured to operate on said evaluable time-varying signal to determine a largest magnitude of said evaluable time-varying signal within said at least one signal segment, and wherein said evaluation stage is further configured to generate a morphology code, wherein said morphology code comprises a pattern subcode that represents a pattern of said magnitudes of said evaluable time-varying signal at said curve points relative to said largest magnitude of said evaluable time-varying signal within said at least one signal segment, and wherein said morphology code further comprises an amplitude subcode that represents said largest magnitude of said evaluable time-varying signal within said at least one signal segment.