Signal processing apparatus

A patient monitoring apparatus comprising:

• a light-sensitive detector configured to detect light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood and configured to output one or more output signals based on the detected light;
• and
• an electronic processing system (i) programmed to be capable of utilizing a first calculation technique adapted to remove motion induced noise from one of the one or more output signals, and (ii) programmed to be capable of utilizing a second calculation technique different from the first calculation technique, wherein the electronic processing system determines a value indicative of a physiological parameter through utilization of at least one of the first and second calculation techniques.

A method of determining a physiological characteristic of pulsing blood, the method comprising:

• receiving first and second intensity signals from a light-sensitive detector which detects light of at least first and second wavelengths transmitted through body tissue carrying pulsing blood;
• and
• utilizing at least one of at least first and second calculation techniques to determine a value indicative of the physiological parameter based upon at least one of the first and second intensity signals, wherein the utilizing comprises qualifying the value for inclusion, depending upon different conditions of the first and second intensity signals, and wherein the first calculation technique is different from the second calculation technique.

A patient monitoring apparatus comprising:

• a light-sensitive detector configured to detect light of at least first and second wavelengths attenuated by body tissue carrying pulsing blood and configured to output one or more output signals based on the detected light;
• and
• an electronic processing system (i) programmed to be capable of utilizing a first calculation technique to determine at least a first value representative of the at least one physiological characteristic of the pulsing blood based on at least one of the one or more output signals, (ii) programmed to be capable of utilizing a second calculation technique different from the first calculation technique, and (iii) programmed to utilize at least one of the first and second calculation techniques based at least in pat on a property of the one or more output signals to determine a value indicative of the at least one physiological characteristic.