Abstract:
A low power pulse oximeter includes an input stage for amplifying a signal received from a light detector that is switchably connected to the power supply that powers the amplifier. The oximeter also includes an output stage with an LED driver circuit that is switchably connected to the power supply that powers the LED driver circuit. The input and output stages are switchably connected to the power supply when measurements need to be taken. When measurements do not need to be taken, they are switched off to reduce the power consumption of the oximeter.
Abstract:
Systems and methods for measuring signals representative of muscle activity are provided. One method includes detecting an ECG signal through a plurality of electrodes. The ECG signal includes a plurality of ECG sample signals, and each ECG sample signal is a bipolar signal associated with two of the plurality of electrodes and includes a cardiac signal component and a myographic signal component. The method further includes filtering each of the ECG sample signals to remove at least a portion of the cardiac signal component and generate a combined myographic power signal for the two of the plurality of electrodes with which the ECG sample signal is associated. Each combined myographic power signal represents a myographic potential between the two electrodes. The method further includes calculating individual myographic power signals for each of the plurality of electrodes by applying the combined myographic power signals within a covariance matrix.
Abstract:
Disclosed embodiments include a method for measuring non-invasive blood pressure from an oscillometric signal and a cuff pressure signal implemented in a medical apparatus comprising: (a) calculating a pulse pressure signal by subtracting an upper and a lower envelope of the oscillometric signal; and (b) calculating without the use of beat detection a mean arterial pressure, a systolic blood pressure, and a diastolic blood pressure from said oscillometric signal, said cuff pressure signal, and a plurality of thresholds a device with at least one processor.
Abstract:
A waveform processor for processing waveforms of the ECG type from surface electrodes connected to the human body. Differential lead waveforms are sampled by a fast, high resolution A/D converter which are thereafter provided to a preprocessor where filtering and a reconstruction of the leads waveforms takes place. The waveforms are then detected, classified, and averaged to form composites of the X, Y, and Z terminal leads. Special filtering is used to detect the high frequency low amplitude features of the composite waveforms.
Abstract:
Systems and methods for use in providing input relating to medical data are provided. A method includes receiving a partial textual input relating to medical data. The method further includes determining one or more suggested input strings associated with the partial textual input. Determining the suggested input string(s) includes: (1) for each of a plurality of reference input strings contained within one or more of a plurality of reference files within a database, identifying a frequency with which the reference input string appears in the plurality of reference files, and (2) determining the suggested input string(s) further includes determining the suggested input string(s) from among the plurality of reference input strings based on the frequencies with which the reference input strings appear in the plurality of reference files. The method further includes providing the suggested input string(s) to the user as suggestions for completing the partial textual input.
Abstract:
Systems and methods for measuring signals representative of muscle activity are provided. One method includes detecting an ECG signal through a plurality of electrodes. The ECG signal includes a plurality of ECG sample signals, and each ECG sample signal is a bipolar signal associated with two of the plurality of electrodes and includes a cardiac signal component and a myographic signal component. The method further includes filtering each of the ECG sample signals to remove at least a portion of the cardiac signal component and generate a combined myographic power signal for the two of the plurality of electrodes with which the ECG sample signal is associated. Each combined myographic power signal represents a myographic potential between the two electrodes. The method further includes calculating individual myographic power signals for each of the plurality of electrodes by applying the combined myographic power signals within a covariance matrix.
Abstract:
Systems and methods for monitoring the condition of electrodes used in biological signal measurement are provided. One method includes applying a first test signal having a first frequency to at least one of a plurality of electrodes and applying a second test signal having a second frequency to at least one of the plurality of electrodes. Both frequencies are below a frequency range associated with the biological signal. The method further includes capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals. The method further includes retrieving an output amplitude for each of the plurality of test signals from the output signal and calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals.
Abstract:
A digital telemetry transmitter for transmitting eight channels of diagnostic quality electrocardiographic data has input circuitry for receiving analog EKG signals originating at electrodes on the patient. The input circuitry includes a circuit for ascertaining the impedance of the electrode connection to the patient and to indicate an electrode fault. EKG signals from the input circuit are provided to a digital/analog converter for converting the analog signals into corresponding digital signals. The analog/digital converter may comprise an eight channel, 20-bit converter, sampling the input signals at a frequency of 10 KHz and providing a digital output signal having a frequency of 500 Hz. The output of the analog/digital converter is provided to a microprocessor control which provides a digital EKG modulating output signal. The output signal is periodically inverted to avoid stationarity in the transmitted data. The output signal includes error correction data that enables a receiver for the transmitted data to correct the digital EKG signal for noise. The microprocessor control changes the resolution of the transmitter when large signal changes occur in the data to accommodate such signals and to provide data compression. An rf signal generator generates an rf carrier signal. The modulating output signal of the microprocessor control is provided as a frequency modulating signal to the rf signal generator. The rf signal generator is stabilized against alterations due to reflected antenna loading.
Abstract:
Systems and methods for monitoring the condition of electrodes used in biological signal measurement are provided. One method includes applying a first test signal having a first frequency to at least one of a plurality of electrodes and applying a second test signal having a second frequency to at least one of the plurality of electrodes. Both frequencies are below a frequency range associated with the biological signal. The method further includes capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals. The method further includes retrieving an output amplitude for each of the plurality of test signals from the output signal and calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals.
Abstract:
Systems and methods for monitoring the condition of electrodes used in biological signal measurement are provided. One method includes applying a first test signal having a first frequency to at least one of a plurality of electrodes and applying a second test signal having a second frequency to at least one of the plurality of electrodes. Both frequencies are below a frequency range associated with the biological signal. The method further includes capturing the biological signal while applying the plurality of test signals and generating an output signal that includes both the measured biological signal and the plurality of test signals. The method further includes retrieving an output amplitude for each of the plurality of test signals from the output signal and calculating an estimated impedance for each of the plurality of electrodes based on the retrieved output amplitudes of the plurality of test signals.