Simultaneous signal attenuation measurements utilizing code division multiplexing
First Claim
1. A method for use in operating a signal attenuation measurement device, the measurement device including a source system for generating first and second signals and for transmitting the first and second signals to a medium that attenuates the signals, a detector system for receiving first and second received signals from the medium and for providing a composite detector signal based on the first and second received signals, and a parameter module for determining an attenuation related parameter regarding the medium based on the detector signal, said method comprising:
- processing the detector signal to provide a processed signal for demultiplexing, said processed signal including information regarding the first and second signals; and
code division demultiplexing said processed signal using at least one coded demultiplexing signal, said at least one coded demultiplexing signal including a series of values defining a non-periodic code such that said demultiplexing of said processed signal using said at least one coded demultiplexing signal yields demultiplexed information corresponding to each of said first and second signals;
wherein said demultiplexed information is used by the parameter module for determining the attenuation related parameter regarding the medium.
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Accused Products
Abstract
A pulse oximeter (100) includes two or more light sources (102) for transmitting optical signals through an appendage (103) of patient. The sources (102) are operated to transmit code division multiplexed (CDM) signals. That is, the sources (102) are driven by drives (104) in response to signals from a digital processing unit (116) such that the sources (102) are modulated using different code sequences. The code sequences are preferably non-periodic and may be orthogonal to one another. The use of such CDM signals provides certain advantages related to noise reduction.
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Citations
24 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 first and second signals and for transmitting the first and second signals to a medium that attenuates the signals, a detector system for receiving first and second received signals from the medium and for providing a composite detector signal based on the first and second received signals, and a parameter module for determining an attenuation related parameter regarding the medium based on the detector signal, said method comprising:
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processing the detector signal to provide a processed signal for demultiplexing, said processed signal including information regarding the first and second signals; and
code division demultiplexing said processed signal using at least one coded demultiplexing signal, said at least one coded demultiplexing signal including a series of values defining a non-periodic code such that said demultiplexing of said processed signal using said at least one coded demultiplexing signal yields demultiplexed information corresponding to each of said first and second signals;
wherein said demultiplexed information is used by the parameter module for determining the attenuation related parameter regarding the medium.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification