在分析短时自相关法的基础上,探讨了使用谐波自相关方法进行基音频率提取。首先根据语音信号建立谐波自相关模型,通过最小二乘法提取基音谐波频率。然后根据基音谐波频率建立一个周期单位脉冲序列函数,用该函数加权短时自相关函数计算谐波数。最后利用提取的基音谐波和相应的谐波数目进行基音频率估计。实验表明在较低信噪比时,谐波自相关法基音检测错误率为5.0%,比自相关法降低了13.6%。
The extracting pitch frequency based on the harmonic autocorrelation algorithm is discussed. First, a harmonic autocorrelation model is derived. By this model a least-squares fitting optimization technique is developed to extract a pitch harmonic from the noise speech. Then, the harmonic number is determined by an objective function formulated as the short-time autocorrelation function of the noisy speech weighted an impulse- train. The pitch contour is obtained by pitch harmonic and harmonic number. The experiments show that in low signal-to-noise ratio, the error rate of harmonic autocorrelation method is 5.0% and 13.6% lower than that of autocorrelation method.