Method and apparatus for demodulating signals in a

专利名称：Method and apparatus for demodulating

signals in a pulse oximetry system

发明人：Diab, Mohamed K.,Weber, Walter M.,Al-Ali,

Ammar

申请号：EP06014370.8申请日：19990409公开号：EP1709902A3公开日：20070725

专利附图：

摘要：The invention relates to a pulse oximetry system, comprising a modulationsignal generator, said modulation signal generator generating a first modulation signalcomprising a first pulse which repeats at a first repetition frequency, said modulationsignal generator generating a second modulation signal comprising a second pulse whichalso repeats at said first repetition frequency, said second pulse occurring at non-overlapping times with respect to said first pulse; a first transmitter which emits

electromagnetic energy at a first wavelength in response to said first pulse; a secondtransmitter which emits electromagnetic energy at a second wavelength in response tosaid second pulse; a detector which receives electromagnetic energy at said first andsecond wavelengths after passing through a portion of a subject and which generates adetector output signal responsive to the received electromagnetic energy, said detectoroutput signal including a signal component responsive to attenuation of said

electromagnetic energy at said first wavelength and a signal component responsive toattenuation of said electromagnetic energy at said second wavelength; an analog todigital converter which converts said detector output into a sequence of digital values; adecimator which decimates said sequence of digital values to produce a first decimatedsequence according to a first decimation rate; a first demodulator which multiplies saidfirst decimated sequence by a first demodulation sequence and generates a firstdemodulated output signal; a second demodulator which multiplies said decimatedsequence by a second demodulation sequence and generates a second demodulatedoutput signal; and a third demodulator which multiplies said decimated sequence by athird demodulation sequence and generates a noise estimate, said noise estimateprovided to an input of an adaptive algorithm, said adaptive algorithm configured toselect said first demodulation sequence to reduce noise in said first demodulated outputsignal and to select said second demodulation sequence to reduce noise in said seconddemodulated output signal.

申请人：Masimo Corporation

地址：2852 Kelvin Avenue Irvine, CA 92614 US

国籍：US

代理机构：Vossius & Partner

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