Photoplethysmographics using energy-reducing waveform shaping
First Claim
1. A device for collecting photoplethysmographic data, comprisingmeans for generating a first and a second signal, said first and second signals each comprising at least one carrier component, each said carrier component having a component energy, wherein at least one of said first and second signals has a plurality of said carrier components and has an energy less than the sum of its respective component energies;
- means for applying said first and second signal to a modulating medium;
means for detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and
means for generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal.
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Accused Products
Abstract
A method of energy-reducing waveform shaping of carrier signals in a photoplethysmographic system, in which a carrier signal may comprise a time-varying periodic waveform comprising a sum of carrier components. The carrier signal has its energy reduced by adding additional carrier components, which reduce the energy envelope for a period of the carrier signal, while preserving the signal information. The method of energy-reducing waveform shaping may be coupled with frequency-division, phase-division and component-amplitude-division multiplexing, and more generally with any method of multiplexing which employs a time-varying periodic carrier signal. Redundant information may be used for error detection and correction. A plurality of carrier components may be chosen which reduces the energy envelope for a period of the carrier signal, and which employs more carrier components than needed to perform the preferred form of multiplexing and demultiplexing of the modulation effects introduced by a tissue section of the patient. Majority voting of carrier components may then provide for error detection and correction.
115 Citations
51 Claims
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1. A device for collecting photoplethysmographic data, comprising
means for generating a first and a second signal, said first and second signals each comprising at least one carrier component, each said carrier component having a component energy, wherein at least one of said first and second signals has a plurality of said carrier components and has an energy less than the sum of its respective component energies; -
means for applying said first and second signal to a modulating medium; means for detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and means for generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal. - 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, 25)
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26. A device for collecting photoplethysmographic data, comprising
means for generating a first and a second signal, said first and second signals each comprising at least one carrier component, each said carrier component having a component energy, wherein said first signal has a plurality of said carrier components and has an energy less than the sum of its component energies; -
means for applying said first and second signal to a modulating medium; means for detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and means for generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal.
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27. A device for collecting photoplethysmographic data, comprising
means for generating a plurality of signals, said plurality of signals each comprising at least one component signal, each said component signal having a component energy, wherein at least one of said plurality of signals has a plurality of said carrier components and has an energy less than the sum of its respective component energies; -
means for applying said plurality of signals to a modulating medium; means for detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and means for generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal.
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28. A method for collecting photoplethysmographic data, comprising the steps of
generating a first and a second signal, said first and second signals each comprising at least one carrier component, each said carrier component having a component energy, wherein at least one of said first and second signals has a plurality of said carrier components and has an energy less than the sum of its respective component energies; -
applying said first and second signal to a modulating medium; detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. A method for collecting photoplethysmographic data, comprising the steps of
generating a first and a second signal, said first and second signals each comprising at least one carrier component, each said carrier component having a component energy, wherein said first signal has a plurality of said carrier components and has an energy less than the sum of its component energies; -
applying said first and second signal to a modulating medium; detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal.
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51. A method for collecting photoplethysmographic data, comprising the steps of
generating a plurality of signals, said plurality of signals each comprising at least one component signal, each said component signal having a component energy, wherein at least one of said plurality of signals has a plurality of said carrier components and has an energy less than the stun of its respective component energies; -
applying said plurality of signals to a modulating medium; detecting a composite signal at an output of said modulating medium, said modulating medium having a first and a second modulating effect; and generating a first and a second output signal responsive to said composite signal, said first output signal corresponding to said first modulating effect applied to said first signal and said second output signal corresponding to said second modulating effect applied to said second signal.
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Specification