System and method for measuring the instantaneous period of a quasi-periodic signal
First Claim
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1. A method of measuring the instantaneous period of a quasi-periodic signal, the method comprising:
- obtaining a quasi-periodic signal;
determining an initial template of a determined size and shift with a computer by;
performing a cross-correlation between the quasi-periodic signal and a template segment of the quasi-periodic signal, the template segment being of a pre-determined size and a pre-determined shift, to obtain a selection coefficient;
incrementing the pre-determined size and the pre-determined shift of the template segment to create an incremented template segment;
repeating the cross-correlation between the quasi-periodic signal and the incremented template segment through a plurality of increments to obtain selection coefficients for each of a plurality of incremented template segments; and
selecting the incremented template with a maximum selection coefficient;
performing a cross-correlation between the initial template and the quasi-periodic signal to obtain an initial correlation signal;
establishing a first correlation threshold;
selecting portions of the quasi-periodic signal that correspond to peaks of the initial correlation signal greater than the first correlation threshold;
counting a number of peaks in the initial correlation signal greater than the first correlation threshold;
averaging the selected portions to create a second template;
performing a cross-correlation between the second template and the quasi-periodic signal to obtain a second correlation signal;
establishing a second correlation threshold; and
counting the number of peaks in the second correlation signal greater than the second correlation threshold;
wherein if the number of peaks counted in the initial correlation signal is greater than or equal to the number of peaks counted in the second correlation signal, measuring the instantaneous period between the peaks in the second correlation signal andwherein if the number of peaks counted in the initial correlation signal is less than the number of peaks counted in the second correlation signal;
selecting the portions of the quasi-periodic signal that correspond to the peaks of the second correlation signal that are greater than the second correlation threshold;
averaging the selected portions of the quasi-periodic signal to create a third template; and
performing a cross-correlation between the third template and the quasi-periodic signal to obtain a third correlation signal.
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Abstract
A method of measuring the instantaneous period of a quasi-periodic signal includes determining an initial template, performing a cross-correlation between the initial template and a quasi-periodic signal and selecting portions of the signal that correspond to the peaks of the correlation signal. The selected portions are then averaged and another cross correlation is performed between the quasi-periodic signal and a template including the averaged selected portions. The instantaneous period is then measured from the correlation signal.
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Citations
10 Claims
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1. A method of measuring the instantaneous period of a quasi-periodic signal, the method comprising:
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obtaining a quasi-periodic signal; determining an initial template of a determined size and shift with a computer by; performing a cross-correlation between the quasi-periodic signal and a template segment of the quasi-periodic signal, the template segment being of a pre-determined size and a pre-determined shift, to obtain a selection coefficient; incrementing the pre-determined size and the pre-determined shift of the template segment to create an incremented template segment; repeating the cross-correlation between the quasi-periodic signal and the incremented template segment through a plurality of increments to obtain selection coefficients for each of a plurality of incremented template segments; and selecting the incremented template with a maximum selection coefficient; performing a cross-correlation between the initial template and the quasi-periodic signal to obtain an initial correlation signal; establishing a first correlation threshold; selecting portions of the quasi-periodic signal that correspond to peaks of the initial correlation signal greater than the first correlation threshold; counting a number of peaks in the initial correlation signal greater than the first correlation threshold; averaging the selected portions to create a second template; performing a cross-correlation between the second template and the quasi-periodic signal to obtain a second correlation signal; establishing a second correlation threshold; and counting the number of peaks in the second correlation signal greater than the second correlation threshold; wherein if the number of peaks counted in the initial correlation signal is greater than or equal to the number of peaks counted in the second correlation signal, measuring the instantaneous period between the peaks in the second correlation signal and wherein if the number of peaks counted in the initial correlation signal is less than the number of peaks counted in the second correlation signal; selecting the portions of the quasi-periodic signal that correspond to the peaks of the second correlation signal that are greater than the second correlation threshold; averaging the selected portions of the quasi-periodic signal to create a third template; and performing a cross-correlation between the third template and the quasi-periodic signal to obtain a third correlation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of measuring an instantaneous period of a quasi-periodic signal, the method comprising:
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obtaining a quasi-periodic signal; determining an initial template of a determined size and shift with a computer by; performing a cross-correlation between the quasi-periodic signal and a template segment of the quasi-periodic signal to obtain a selection coefficient, the template segment being of a pre-determined size and a pre-determined shift; and incrementing the pre-determined size and a pre-determined shift of the template segment to create an incremented template segment; repeating the cross-correlation between the quasi-periodic signal and the incremented template segment through a plurality of increments to obtain selection coefficients for each of a plurality of incremented template segments; and selecting the incremented template with a maximum selection coefficient as the initial template; performing a cross-correlation between an initial template and the quasi-periodic signal to obtain an initial correlation signal; counting peaks of the initial correlation signal greater than a first correlation threshold; selecting portions of the quasi-periodic signal that correspond to the peaks of the initial correlation signal greater than the first correlation threshold; averaging the selected portions of the quasi-periodic signal to create a second template; performing a cross-correlation between the second template and the quasi-periodic signal to obtain a second correlation signal; and counting peaks of the second correlation signal greater than the correlation threshold; wherein if the second correlation signal has more counted peaks than the initial correlation signal, using the second template as the initial template and iteratively repeating the method until the initial correlation signal has a same number or more counted peaks than the second correlation signal; and wherein if the initial correlation signal has the same number or more counted peaks than the second correlation signal, measuring the instantaneous period from the first correlation signal. - View Dependent Claims (10)
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Specification