 Exciter-detector unit for measuring physiological parameters |
| This invention relates generally to an exciter-detector unit and more particularly to an assembly ... |
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| Patient cable connector |
| The present invention involves a connector that is configured to attach both disposable and durable ... |
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| Pulse oximetry sensor adapter |
| A drawback to conventional pulse oximetry systems is the lack of standardization of the sensor and ... |
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| Signal processing apparatus and method |
| The present invention involves several different embodiments using the novel signal model in ... |
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| Rapid non-invasive blood pressure measuring device |
| The present invention is a method and apparatus for quickly determining a blood pressure value at a ... |
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| Apparatus and method for measuring an induced perturbation to determine a physiological parameter |
| OF THE PREFERRED EMBODIMENTS A preferred embodiment concentrates on the physiological parameter of ... |
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| Signal processing apparatus |
| This invention provides improvements upon the methods and apparatus disclosed in U.S. patent ... |
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| Blood glucose monitoring system |
| Due to the parameters required by the Beer-Lambert law, the difficulties in detecting glucose ... |
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| Circuit board based cable connector |
| Accordingly, the present invention involves a connector that is configured to attach sensors to ... |
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| Patient cable sensor switch |
| A drawback to conventional pulse oximetry systems is the lack of standardization of the sensor and ... |
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Signal processing apparatus
| Details |
Inventors: Diab, Mohamed K.; Kiani-Azarbayjany, Esmaiel; Weber, Walter M.;
Assignee: Masimo Corporation (Mission Viejo, CA)
Primary Examiner: Sykes; Angela D.
Assistant Examiner:
Attorney, Agent or Firm: Knobbe, Martens, Olson & Bear
A signal processor which acquires a first signal, including a first primary signal portion and a first secondary signal portion, and a second signal, including a second primary signal portion and a second secondary signal portion, wherein the first and second primary signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor of the present invention generates a primary or secondary reference signal which is a combination, respectively, of only the primary or secondary signal portions. The secondary reference signal is then used to remove the secondary portion of each of the first and second measured signals via a correlation canceler, such as an adaptive noise canceler, preferably of the joint process estimator type. The primary reference signal is used to remove the primary portion of each of the first and second measured signals via a correlation canceler. The processor of the present invention may be employed in conjunction with a correlation canceler in physiological monitors wherein the known properties of energy attenuation through a medium are used to determine physiological characteristics of the medium. Many physiological conditions, such as the pulse, or blood pressure of a patient or the concentration of a constituent in a medium, can be determined from the primary or secondary portions of the signal after other signal portion is removed. |
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DETAILED DESCRIPTION This invention is an improvement of U.
S.
patent application Ser.
No.
07/666,060 filed Mar.
7, 1991 and entitled Signal Processing Apparatus and Method, which earlier application has been assigned to the assignee of the instant application.
The invention is a signal processor which acquires a first signal and a second signal that is correlated to the first signal.
The first signal comprises a first primary signal portion and a first secondary signal portion.
The second signal comprises a second primary signal portion and a second secondary signal portion.
The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection.
Alternatively, the signals may be acquired by measuring energy generated by the medium.
The first and second measured signals are processed to generate a secondary reference which does not contain the primary signal portions from either of the first or second measured signals.
The remaining secondary signal portions from the first and second measured signals are combined to form the secondary reference.
This secondary reference is correlated to the secondary signal portion of each of the first and second measured signals.
The secondary reference is then used to remove the secondary portion of each of the first and second measured signals via a correlation canceler, such as an adaptive noise canceler.
The correlation canceler is a device which takes a first and second input and removes from the first input all signal components which are correlated to the second input.
Any unit which performs or nearly performs this function is herein considered to be a correlation canceler.
An adaptive correlation canceler can be described by analogy to a dynamic multiple notch filter which dynamically changes its transfer function in response to a reference signal and the measured signals to remove frequencies from the measured signals that are also present in the reference signal.
Thus, a typical adaptive correlation canceler receives the signal from which it is desired to remove a component and a reference signal
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Communications 
