9. The speech processor in claim 7, further comprising: a pitch counter circuit which compares the values of the auto-correlation function for a sequence of pitches and determines when the autocorrelation value crosses some predetermined threshold, a new reference pitch being inserted in said encoded signal when said value of said auto-correlation function drops below said threshold.
9. The speech processor in claim 7, further comprising: a pitch counter circuit which compares the values of the auto-correlation function for a sequence of pitches and determines when the autocorrelation value crosses some predetermined threshold, a new reference pitch being inserted in said encoded signal when said value of said auto-correlation function drops below said threshold. 10. The speech processor in claim 9, wherein said autocorrelation threshold is set in the range between about 0.7 and 0.9.