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US 6,216,094 B1Granted
Method of and apparatus for analyzing a signal
AssigneeMonitoring Technology Corporation
InventorsRobert Anthony Fox Linton, David Marston Band, Nicholas William Fox Linton
Life of this patent
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Abstract
A method of analyzing a signal representing a physical parameter to obtain information from said signal and to extrapolate information contained in said signal and/or to ignore an interfering component in part of said signal, said signal representing either only a first portion of a skew distribution, or a first portion of a skew distribution and a second portion containing an interfering component, in which the area of a skew distribution, preferably a lognormal distribution is measured. The method is particularly applicable to the measurement of cardiac output. Apparatus for carrying out the method is also disclosed.
Claims38
A method of analyzing a signal representing a physical parameter for at least one of the purposes:
- (i) to obtain information from said signal, (ii) to extrapolate information contained in said signal and (iii) to ignore an interfering component in part of said signal, said signal representing one of the group consisting of only a first portion of a skew distribution, and a first portion of a skew distribution, and a second portion containing said interfering component, said method comprising the steps of:
- a) selecting two fractions of the maximum value of said signal in said first portion and selecting whether said fractions are to represent positions on said skew distribution having a positive or negative slope, said fractions being used to delineate between first and second parts of said skew distribution, said first and second parts being delineated to lie within said first portion of said skew distribution,
- b) determining the integrals of said first and second parts, and
- c) determining the integrals of said complete skew distribution using said determined integrals of said first and second parts and a predetermined relationship between the integral of a complete skew distribution and functions of integrals of said first and second parts for said selected fractions.
1 more element
A method of determining the flow rate of a fluid comprising the steps of:
- a) adding a known quantity of a substance to said fluid at a point in time,
- b) measuring the quantity of said substance in said fluid at a point downstream to generate a distribution with respect to time, said distribution approximating either only a first portion of a skew distribution, or a first portion of a skew distribution and a second portion containing extraneous components,
- c) assuming said distribution can be approximated by a skew distribution and selecting two fractions of the maximum value of said signal in said first portion and selecting whether said fractions are to represent positions on said skew distribution having a positive or a negative slope, said fractions being used to delineate between first and second parts of said skew distribution, said first and second parts being delineated to lie within said first portion of said skew distribution,
- d) calculating the integrals of said first and second parts,
- e) determining the integral of the complete skew distribution using said calculated integrals of said first and second parts and a predetermined relationship between functions of the integrals of said first and second parts and the integral of said complete skew distribution for said selected fractions, and
- f) calculating the flow rate of said fluid from said known quantity of said substance and said integral of said complete skew distribution.
3 more elements
Apparatus for analyzing a signal representing a physical parameter for at least one of the purposes:
- (i) to obtain information from said signal, (ii) to extrapolate information contained in said signal and (iii) to ignore an interfering component in part of said signal, said signal representing one of a group consisting of only a first portion of a skew distribution and a first portion of a skew distribution, and a second portion containing said interfering component, said system comprising:
- a) means for selecting two fractions of the maximum value of said signal in said first portion and selecting whether said fractions are to represent positions on said skew distribution having a positive or a negative slope, said fractions being used to delineate between first and second parts of said skew distribution, said first and second parts being delineated to lie within said first portion of said skew distribution,
- b) means for determining the integrals of said first and second parts, and
- c) means for determining the integrals of said complete skew distribution using said determined integrals of said first and second parts and a predetermined relationship between the integral of a complete skew distribution and functions of integrals of said first and second parts for said selected fractions.
1 more element
Apparatus for determining the flow rate of a fluid comprising:
- a) sensor means for measuring the quantity of a substance in said fluid at a point downstream of where a known quantity said substance has been added to said fluid, the measurement generating a distribution with respect to time which approximates either only a first portion of a skew distribution, or a first portion of a skew distribution and a second portion containing extraneous components,
- b) means for selecting two fractions of the maximum value of said signal in said first portion and selecting whether said fractions are to represent positions on said skew distribution having a positive or a negative slope, said fractions being used to delineate between first and second parts of said skew distribution, said first and second parts being delineated to lie within said first portion of said skew distribution,
- c) means for calculating the integrals of said first and second parts,
- d) means for determining the integral of the complete skew distribution using said calculated integrals of said first and second parts and a predetermined relationship between functions of integrals of said first and second parts and the integral of said complete skew distribution for said selected fractions, and
- e) means for calculating the flow rate of said fluid from said known quantity of said substance and said integral of said complete skew distribution.
2 more elements
Dependencies are inferred from the claim text.