Patent ID: 7806825

Claim:
A medical signal processing method, comprising the steps of: receiving, at a processor of a medical device, time-based information corresponding to a defined time interval of a time-based, medical diagnostic signal that has been modulated based on interaction with at least one of tissue and fluid of a patient; performing, using said processor, a transform on said time-based information to obtain a frequency spectrum defined by a set of nonzero amplitude values, calculated directly from said transform, for a corresponding set of frequencies, said frequency spectrum including a number of said nonzero amplitude values at irregularly spaced frequency intervals, wherein said nonzero amplitude values include a first nonzero amplitude value at a first frequency value and a second nonzero amplitude value greater than said first nonzero amplitude value at a second frequency and said second frequency is a noninteger multiple of each frequency of said set of frequencies other than said second frequency, said step of performing a transform comprising representing said time-based medical diagnostic signal as a series of piecewise function segments; and operating said processor in a signal processing environment for using said transform to provide an output, including diagnostic information concerning said at least one of tissue and fluid of said patient, based on said time-based, medical diagnostic signal; wherein said time-based signal is an analog signal and said time-based information is digital time-based information, and said step of performing a transform involves accounting for a digitization error associated with a difference between said analog time-based signal and said digital time-based information, and further wherein said digital time-based information comprises a time series of digital values and said accounting involves defining a number of value ranges associated with said digital values, establishing a mathematical model defining a process for deriving said spectrum wherein a given digital value of said series of digital values is allowed to vary within one of said number of value ranges including said given digital value as part of said process, and using said mathematical model to derive said spectrum.