Simultaneous signal attenuation measurements utilizing frequency orthogonal random codes
First Claim
1. A method for use in operating a signal attenuation measurement device, the measurement device including a source system for generating at least first and second signals and for transmitting the first and second signals to a patient tissue site that attenuates the signals, a detector system for receiving at least first and second attenuated signals from the patient tissue site corresponding with the first and second signals transmitted to the patient tissues site and for providing a composite detector signal based on the first and second attenuated signals, and a parameter estimation module for determining a physiological parameter regarding the patient based on information included in the detector signal, said method comprising:
- operating the source system to multiplex the first and second signals in accordance with first and second frequency orthogonal code division multiplexed excitation waveforms;
processing the detector signal to provide a processed signal for demultiplexing, the processed signal including information regarding the first and second attenuated signals; and
demultiplexing the processed signal using at least one demultiplexing signal, said at least one demultiplexing signal including a series of values corresponding with one of the first and second frequency orthogonal code division multiplexed waveforms such that said step of demultiplexing the processed signal yields demultiplexed information corresponding to each of the first and second attenuated signals;
wherein said demultiplexed information is usable by the parameter estimation module for determining the physiological parameter regarding the patient.
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Abstract
A method for use in operating a signal attenuation measurement device used to obtain a physiological parameter of a patient and an apparatus for use in determining at least one physiological parameter relating to a patient from at least first and second signals transmitted to a patient tissue site and attenuated thereby are provided. In accordance with the method and apparatus of the present invention, the first and second signals are multiplexed using frequency orthogonal code division multiplexed excitation waveforms. This allows for both relatively good source separation of the signals and whitening of external noise.
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Citations
31 Claims
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1. A method for use in operating a signal attenuation measurement device, the measurement device including a source system for generating at least first and second signals and for transmitting the first and second signals to a patient tissue site that attenuates the signals, a detector system for receiving at least first and second attenuated signals from the patient tissue site corresponding with the first and second signals transmitted to the patient tissues site and for providing a composite detector signal based on the first and second attenuated signals, and a parameter estimation module for determining a physiological parameter regarding the patient based on information included in the detector signal, said method comprising:
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operating the source system to multiplex the first and second signals in accordance with first and second frequency orthogonal code division multiplexed excitation waveforms;
processing the detector signal to provide a processed signal for demultiplexing, the processed signal including information regarding the first and second attenuated signals; and
demultiplexing the processed signal using at least one demultiplexing signal, said at least one demultiplexing signal including a series of values corresponding with one of the first and second frequency orthogonal code division multiplexed waveforms such that said step of demultiplexing the processed signal yields demultiplexed information corresponding to each of the first and second attenuated signals;
wherein said demultiplexed information is usable by the parameter estimation module for determining the physiological parameter regarding the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus for use in determining at least one physiological parameter relating to a patient from at least first and second signals transmitted to a patient tissue site and attenuated thereby, said apparatus comprising:
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a source system operative to generate the first and second signals and transmit the first and second signals to the patient tissue site;
a detector system operative to receive first and second attenuated signals from the patient tissue site corresponding with the first and second signals transmitted to the patient tissues site and provide a composite detector signal based on the first and second attenuated signals; and
a signal processing device including;
a code generation module operative to drive the source system to multiplex the first and second signals in accordance with first and second frequency orthogonal code division multiplexed excitation waveforms; and
a demodulation module operative to demultiplex the composite detector signal using at least one demultiplexing signal, said at least one demultiplexing signal including a series of values corresponding with one of the first and second frequency orthogonal code division multiplexed waveforms to obtain demultiplexed information corresponding to each of the first and second attenuated signals, the demultiplexed information being usable in determining the physiological parameter regarding the patient. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification