Method and apparatus for speech analysis and synthesis using lattice ladder notch filters
First Claim
1. A speech analyzer for speech segmented into a plurality of speech frames comprising:
- means for determining filter zeros and covariances from a speech frame, and means for calculating a set of gains for an LLN filter which match said filter zeros and covariances so that as said LLN filter is excited by a selected signal said speech frame is regenerated.
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Abstract
A method and apparatus for analyzing and synthesizing speech includes a programmable lattice-ladder notch filter which may be programmed to exhibit both filter poles and filter zeros and thereby exhibit a power spectral density with a better fit to that of a speech frame such that, when energized by a selected signal sample, a more accurate regeneration of speech is achieved. The filter parameters may be reliably and systematically determined as a single solution to a mathematical analysis given a set of gain parameters matching the observed covariance data and having a prescribed set of transmission zeros. These transmission zeros may either be preselected as a design specification, or recovered from analysis of the speech data. A speech frame may be analyzed and provide a set of parameters which may be transmitted to a remote location where a synthesizer may accurately reproduce the speech frame.
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Citations
32 Claims
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1. A speech analyzer for speech segmented into a plurality of speech frames comprising:
- means for determining filter zeros and covariances from a speech frame, and means for calculating a set of gains for an LLN filter which match said filter zeros and covariances so that as said LLN filter is excited by a selected signal said speech frame is regenerated.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- 18. A speech synthesizer having a programmable LLN filter, and an excitation generator for generating a pre-selected signal for exciting said LLN filter to thereby regenerate a desired frame of speech.
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22. A method for analyzing a frame of speech comprising the steps of:
- determining a set of filter zeros and covariances from said speech frame, and calculating therefrom a set of filter parameters comprising a set of gains for an LLN filter which match said filter zeros and covariances so that as said LLN filter is excited by a preselected signal said speech frame is regenerated.
- View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A method for regenerating a frame of speech comprising the steps of:
- programming a programmable LLN filter, generating a pre-selected signal for exciting said LLN filter, and exciting said LLN filter with said generated signal to thereby regenerate said frame of speech.
- View Dependent Claims (30, 31)
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32. A speech analyzer including a circuit for detecting a frame of speech, and a translator of converting said speech frame into a set of LLN filter parameters, said LLN filter parameters being suitable for reproduction of said speech frame through excitation of an LLN filter configured with said filter parameters.
Specification