Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may receive a calculated value indicative of a physiological rate. The system may generate value pairs from a first collection of values of the physiological signal and another collection of corresponding value of the physiological signal spaced from the first collection based on the calculated value. The system may determine a best fit linear relationship based on the value pairs and determine at least one statistical metric based on the linear relationship and the value pairs. The system may qualify or disqualify the calculated value based on the at least one statistical metric.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may condition the physiological signal to assist in the determination of the physiological information. The system may generate a positive signal and a negative signal based on respective positive and negative values of the physiological signal. The system may filter the positive and negative signals, combine the filtered signals, and modify the physiological signal based on the combined signal. The physiological signal may be modified, for example, by subtracting the combined signal from the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a first difference signal based on the physiological signal. The system may sort the first difference signal to generate a sorted difference signal. The system may generate a second difference signal based on the sorted difference signal. The system may determine an algorithm setting based on the second difference signal. The algorithm setting may, for example, affect the amount of filtering applied to the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may condition the physiological signal to assist in the determination of the physiological information. The system may generate a signal based on a stability function applied to the physiological signal. The stability function may include a Lyapunov function. The system may generate a difference signal based on the stability function, and modify the physiological signal based on the difference signal. The modification may include reducing, or otherwise limiting, some differences between adjacent values in the physiological signal, removing portions of the physiological signal, or other modifications.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a window of data, and determine physiological information based on the window of data. The generated window of data may include one or more samples of physiological data, from the physiological signal, and one or more initialization values. The initialization values may include random numbers, noise values, sample values, scaled values thereof, or a combination thereof.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may apply a digital filter to the physiological signal to assist in the determination of the physiological information. The system may determine a metric based on the physiological signal, and selectively apply the digital filter to the physiological signal based on the metric. The digital filter, which may include two or more filter coefficients, may correspond to a weighted sum of the physiological signal and a difference signal corresponding to the physiological signal. The filter coefficients may be adjustable, allowing selectivity in the characteristics of the digital filter between weighting the physiological signal and difference signal.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a lag matrix, which includes multiple segments of the physiological signal each having the same number of values. The system may generate a correlation matrix, which includes multiple correlation values, based on the lag matrix. The system may identify a peak in the correlation lag matrix, or a processed matrix derived thereof, and the corresponding lag value. The correlation matrix, or processed matrix thereof, may be rotated, averaged, or otherwise transformed by the system to identify the lag value. The system may determine physiological rate information based on the identified lag value.

Abstract: A physiological monitoring system may process a physiological signal such a photoplethysmograph signal from a subject. The system may determine physiological information, such as a physiological rate, from the physiological signal. The system may use search techniques and qualification techniques to determine one or more initialization parameters. The initialization parameters may be used to calculate and qualify a physiological rate. The system may use signal conditioning to reduce noise in the physiological signal and to improve the determination of physiological information. The system may use qualification techniques to confirm determined physiological parameters. The system may also use autocorrelation techniques, cross-correlation techniques, fast start techniques, and/or reference waveforms when processing the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, and other information, such as noise information, from a physiological signal. The system may generate a first difference signal based on a first segment of the physiological signal and sort the first difference signal to generate a first sorted difference signal. The system may generate a second difference signal based on a second segment of the physiological signal and sort the second difference signal to generate a second sorted difference signal. The first and second sorted difference signals may be analyzed and a value indicative of noise may be determined based on the analysis.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may condition the physiological signal to assist in the determination of the physiological information. The system may generate absolute values of the physiological signal, filter the absolute values, and modify the physiological signal based on the filtered signal. The filtered signal may be shifted in amplitude prior to modifying the physiological signal. The modification may include dividing the physiological signal by the filtered signal to normalize the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may determine a skew metric based on the physiological signal. The system may also determine a correlation lag value corresponding to a peak in a correlation sequence derived from the physiological signal. The system may qualify or disqualify the correlation lag value based on the skew metric. The system may, for example, compare the skew metric and the correlation lag value to a reference set of skew metric values and correlation lag values to determine whether to qualify or disqualify the correlation lag value.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may receive a calculated value indicative of a physiological rate. Based on the value, the system may select pairs of values of the physiological signal that are particularly spaced. The system may determine a state for each pair of values. The state may correspond to a set of criteria such as, for example, equalities, inequalities, logical operators, or other criteria. The system may determine a number of state transitions based on the determined states, and qualify or disqualify the calculated value based on the number of state transitions.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may receive a calculated value indicative of a physiological rate. The system may determine a value indicative of noise in the physiological signal and adjust at least one criterion for qualifying or disqualifying the calculated value based on the value indicative of noise. The criterion may, for example, be a threshold and the threshold may be adjusted based on the value indicative of noise. The system may qualify or disqualify the calculated value based on the at least one adjusted criterion.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may determine a first metric value indicative of a physiological classification based on the physiological signal. An algorithm setting may be determined based on the physiological classification. The system may determine a second metric value indicative of a different physiological classification based on the physiological signal. A different algorithm may be determined based on the different physiological classification. The algorithm setting may, for example, affect the amount of filtering applied to the physiological signal.

Abstract: A physiological monitoring system may determine physiological information, such as physiological rate information, from a physiological signal. The system may generate a correlation sequence using two segments of the physiological signal. The system may determine a first correlation lag value that corresponds to a peak in the correlation sequence, and also determine a second correlation lag value equal to a fraction of the first correlation lag value. The fraction may be, for example, one half. The system may qualify or disqualify the correlation lag value based on the correlation value at the second lag value. The system may compare the correlation value at the second lag value to a threshold, to the correlation sequence at the first lag value, or both.