Methods and apparatus for detecting harmonic structure in a waveform
First Claim
1. A method of using a computer processor to analyze electrical signals and input data representative of sounds to determine the periodicity of a waveform represented by said data, which method comprises using the computer processor to process said input data to obtain log power spectrum data representing a log power spectrum of said input data, using the computer processor to apply an autocorrelation function of limited order to said log power spectrum data to obtain autocorrelation data, and thereby determining an estimate of the periodicity of said waveform.
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Abstract
The periodicity of a signal from a voice channel is determined by sampling the signal, computing the log power spectrum, optionally thresholding and differencing the power spectrum, and then performing an autocorrelation function of limited order to confine the search for periodicity to spans of up to about 400 Hz to 500 Hz.
30 Citations
10 Claims
- 1. A method of using a computer processor to analyze electrical signals and input data representative of sounds to determine the periodicity of a waveform represented by said data, which method comprises using the computer processor to process said input data to obtain log power spectrum data representing a log power spectrum of said input data, using the computer processor to apply an autocorrelation function of limited order to said log power spectrum data to obtain autocorrelation data, and thereby determining an estimate of the periodicity of said waveform.
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10. Apparatus for digitally processing input data representative of sounds to estimate periodicity of a waveform of the input data, said apparatus comprising:
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input means for inputting the input data representative of sounds in the form of electrical signals, processing means comprising a computer processor for processing the input data from said input means to obtain log power spectrum data representative of a log power spectrum of said input data, autocorrelation means comprising the computer processor for autocorrelating said log spectrum data; and means responsive to said autocorrelation data comprising the computer processor to determine an estimate of the periodicity of said waveform.
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Specification