Signal component processor

A pulse oximeter system comprising:

• an input capable of accepting a physiological signal;
• and
• a component processor capable of communicating with said input and comprising:
• a first calculator capable of determining a basis function index from said signal;
• and
• a second calculator capable of generating a basis function waveform according to said index, deriving a component from said sensor signal and said waveform, and generating a physiological measurement responsive to said component, wherein said first calculator determines a basis function frequency as said basis function index, and said second calculator generates a sinusoid at said frequency as said basis function waveform.

A signal processing method comprising the steps of:

• receiving a sensor signal;
• calculating an estimated pulse rate;
• determining an optimization of said sensor signal proximate said estimated pulse rate;
• defining a frequency corresponding to said optimization;
• and
• outputting a physiological measurement responsive to a component of said sensor signal at said frequency, and
• wherein said outputting step comprises the substeps of:
• inputting a red (RD) portion and an infrared (IR) portion of said sensor signal;
• deriving a RD component of said RD portion and an IR component of said IR portion corresponding to said frequency;
• and
• computing an oxygen saturation based upon a magnitude ratio of said RD component and said IR component;
• and
• wherein said deriving step comprises the substeps of:
• generating a sinusoidal waveform at said frequency;
• and
• selecting said RD component and said IR component utilizing said waveform.

A signal processor comprising:

• a first calculator means for deriving an optimization frequency from a pulse rate estimate and a sensor signal;
• and
• a second calculator means for deriving a physiological measurement responsive to a sensor signal component at said frequency,
• wherein said first calculator means comprises:
• a signal component transform means for determining a plurality of signal values corresponding to a plurality of selected frequencies within a window including said pulse rate estimate;
• and
• a detection means for determining a particular one of said selected frequencies corresponding to an optimization of said sensor signal;
• and
• wherein said second calculator means comprises:
• a waveform means for generating a sinusoidal signal at said frequency;
• a frequency selection means for determining a component of said sensor signal from said sinusoidal signal;
• and
• a calculator means for deriving a ratio responsive to said component.