Signal processing apparatus

a signal processing and signal technology, applied in the field of signal processing, can solve the problems of distorting the measured signal, ineffective conventional filtering techniques in extracting either the primary or secondary signal, and erratic energy attenuation

USRE38476E1Inactive Publication Date: 2004-03-30JPMORGAN CHASE BANK NA
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Patents(United States)
Current Assignee / Owner
Publication Date
2004-03-30
Estimated Expiration
Not applicable · inactive patent

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Abstract

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.
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Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to the field of signal processing. More specifically, the present invention relates to the processing of measured signals, containing a primary signal portion and a secondary signal portion, for the removal or deviation of either the primary or secondary signal portion when little is known about either of these components. More particularly, the present invention relates to modeling the measured signals in a novel way which facilitates minimizing the correlation between the primary signal portion and the secondary signal portion in order to produce a primary and / or secondary signal. The present invention is especially useful for physiological monitoring systems including blood oxygen saturation systems.2. Description of the Related ArtSignal processors are typically employed to remove or derive either the primary or secondary signal portion from a composite measured signal including a primary signal po...

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Embodiment Construction

The present invention involves a system which utilizes first and second measured signals that each contain a primary signal portion and a secondary signal portion. In other words, given a first and second composite signals S.sub.1 (t)=s.sub.1 (t)+n.sub.1 (t) and S.sub.2 (t)=s.sub.2 (t), the system of the present invention can be used to isolate either the primary signal portion s(t) or the secondary signal portion n(t). Following processing, the output of the system provides a good approximation n"(t) to the secondary signal portion n(t) or a good approximation s"(t) to the primary signal portion s(t).

The system of the present invention is particularly useful where the primary and / or secondary signal portion n(t) may contain one or more of a constant portion, a predictable portion, an erratic portion, a random portion, etc. The primary signal approximation s"(t) or secondary signal approximation n"(t) is derived by removing as many of the secondary signal portions n(t) or primary si...