Periodic signal processing method, periodic signal conversion method, periodic signal processing device, and periodic signal analysis method
First Claim
1. A periodic signal processing method comprising:
- extracting, from a signal having periodicity, a fundamental period of the signal in a temporal direction;
arranging n sets of time windows such that centers of each of the n sets of time windows are separated by a fraction 1/n of the fundamental period, where n is an integer equal to or larger than 2, so as to extract n sets of portions of different ranges from the signal having periodicity;
calculating n set of power spectrums for the n set of portions extracted by the respective time windows;
adding the whole n sets of power spectrums with a same ratio to obtain a first power spectrum,calculating a second power spectrum by convolving a rectangular smoothing function having a width corresponding to a fundamental frequency in a frequency direction on the obtained first power spectrum,wherein the extracting fundamental period, the arranging time windows, the calculating power spectrums, and the adding at least two of the calculated power spectrums are performed by a processor programmed to perform the extracting fundamental period, the arranging time windows, the calculating power spectrums, and the adding at least two of the calculated power spectrums.
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Abstract
The invention relates to a periodic signal processing method, a periodic signal conversion method, and a periodic signal processing device capable of reducing the influence of periodicity without using a spectral model. Time windows are arranged such that a center of each of the time windows is at a division position which divides a fundamental frequency in a temporal direction into fractions 1/n (where n is an integer equal to or larger than 2) so as to extract a plurality of portions of different ranges from a signal having periodicity. A power spectrum for the plurality of portions extracted by the respective time windows is calculated, and the calculated power spectrum is added with a same ratio.
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Citations
12 Claims
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1. A periodic signal processing method comprising:
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extracting, from a signal having periodicity, a fundamental period of the signal in a temporal direction; arranging n sets of time windows such that centers of each of the n sets of time windows are separated by a fraction 1/n of the fundamental period, where n is an integer equal to or larger than 2, so as to extract n sets of portions of different ranges from the signal having periodicity; calculating n set of power spectrums for the n set of portions extracted by the respective time windows; adding the whole n sets of power spectrums with a same ratio to obtain a first power spectrum, calculating a second power spectrum by convolving a rectangular smoothing function having a width corresponding to a fundamental frequency in a frequency direction on the obtained first power spectrum, wherein the extracting fundamental period, the arranging time windows, the calculating power spectrums, and the adding at least two of the calculated power spectrums are performed by a processor programmed to perform the extracting fundamental period, the arranging time windows, the calculating power spectrums, and the adding at least two of the calculated power spectrums. - View Dependent Claims (2, 3, 4, 5)
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6. A periodic signal processing method, comprising:
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extracting, from a signal having periodicity, a fundamental period of the signal in a temporal direction; arranging n sets of time windows such that centers of each of the n sets of time windows are separated by a fraction 1/n of the fundamental time period, where n is an integer equal to or larger than 2, so as to extract n sets of portions of different ranges from the signal having periodicity; calculating n sets of power spectrums for the n sets of portions extracted by the respective time windows; adding the whole n sets of power spectrums with a same ratio to obtain a first power spectrum; calculating a cumulative sum of the first power spectrum for every predetermined range in the frequency direction; and calculating a difference in the cumulative sum of the first power spectra in the predetermined range between two points at a predetermined interval in the frequency direction and performing linear interpolation to obtain a smoothed power spectrum, wherein the extracting fundamental period, the arranging time windows, the calculating power spectrums, and the adding groups of at least two of the calculated power spectrums are performed by a processor programmed to perform the extracting fundamental period, the arranging time windows, the calculating power spectrums, and the adding groups of at least two of the calculated power spectrums. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A periodic signal processing device, comprising:
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a fundamental period calculation unit configured to extract, from a signal having periodicity, a fundamental period of the signal in a temporal direction; an extraction unit configured to arrange n sets of time windows such that centers of each of the n sets of time windows are separated by a fraction 1/n of the fundamental period, where n is an integer equal to or larger than 2, so as to extract n sets of portions of different ranges from the signal having periodicity; a calculation unit configured to calculate n sets of power spectrums for the n sets of portions extracted by the respective time windows; an addition unit configured to obtain a first power spectrum by adding the whole n sets of power spectrums with a same ratio; and a convolution unit configured to calculate a second power spectrum by convolving a rectangular smoothing function having a width corresponding to a fundamental frequency in a frequency direction on the first power spectrum.
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Specification