Multi-pulse coding system
OwnerTetsu Taguchi, Shigeji Ikedainventors
Life of this patent
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Abstract
A digital speech signal sampled at a predetermined interval is stored in a memory. An LPC (Linear Prediction Coefficient) DDK is developed from the speech signal and thus developed LPC coefficient specifies coefficients of a recursive filter. The speech signal read out from the memory is backwardly supplied to the recursive filter in the reverse order to the sampling order of the speech signal. A plurality of multi-pulses are determined on the basis of the crosscorrelation coefficients (between the speech and an impulse response of the recursive filter) obtained by the recursive filter.
Claims9
A multi-pulse coding system comprising:
- memory means for storing a digital speech signal sampled at a predetermined sampling interval;
- analysis means for developing an LPC (linear predictive coefficient) coefficient by analyzing said speech signal;
- a recursive filter having a coefficient specified by said LPC coefficient;
- supply means for backwardly supplying the speech signal read out from said memory means in the reverse order to the sampling order of said speech signal to said recursive filter to produce crosscorrelation coefficients between said speech signal and an impulse response of said recursive filter;
- and
- multi-pulse determining means for determining a predetermined number of multi-pulses on the basis of said produced crosscorrelation coefficients.
A multi-pulse coding system comprising:
- means for inputting a digital speech signal sampled at a predetermined sampling interval to a memory means;
- analysis means for developing an LPC (linear predictive coefficient) coefficient by analyzing said speech signal;
- a recursive filter having a coefficient specified by said LPC coefficient;
- supply means for backwardly reading out the speech signal from said memory means in the reverse order to the inputting order of said speech signal to said memory means and supplying the read out signal to said recursive filter to produce crosscorrelation coefficients between said speech signal and an impulse response of said recursive filter;
- and
- multi-pulse determining means for determining a predetermined number of multi-pulses on the basis of said produced crosscorrelation coefficients.
A multi-pulse coding method comprising the steps of:
- developing an LPC (Linear Predictive Coefficient) coefficient specifying the coefficient of a recursive filter from a digital speech signal sampled at a predetermined interval;
- backwardly supplying said speech signal in the reverse order to the sampling order of said speech signal to the recursive filter to produce crosscorrelation coefficients between said speech signal and an impulse response of said recursive filter;
- and
- determining a predetermined number of multi-pulses on the basis of said produced crosscorrelation coefficients.
Dependencies are inferred from the claim text.