Improved Pitch Detection Algorithm Based on Autocorrelation Function

An improved pitch detection algorithm based on autocorrelation function is proposed.Unvoiced/voiced decision is realized using the differences between unvoiced and voiced autocorrelation function.Before the pitch detection,the voiced is pretreated by band-pass filter,center clipping and digital filter to reduce the effects of formant and high-frequency noises;after the pitch detection,searching smoothing method is exploited to overcoming the multiple or half frequency errors and random errors.The experimental results show that the performance is superior to traditional autocorrelation function-based algorithm.Furthermore,this new method still works well under low signal noise ratio(SNR=5 dB).