作为语音信号处理中的一项关键技术，基音检测一直是研究热点。本文分析了功率谱二次处理基音检测方法的不足：对于过渡语音，易产生半频或倍频误判；噪声干扰下，检测结果易失真；清、浊音的判断方法复杂。针对这些不足，本文提出一系列改进方法：时域非线性处理，频域加窗滤波，简化清、浊音判断。MATLAB仿真实验结果表明，无论是高信噪比还是低信噪比语音，改进的二次谱法较AMDF法和二次谱法更能清晰、准确地检测出基音轨迹。

As a key technique, the pitch detection has been a hot spot in the field of speech processing. The following three disadvantages of power spectrum reprocessing (PSR) method for pitch detection are found: half pitch error and double pitch error with transition sound; easy distortion in noise speech; the complex method of judging voiceless and voiced speech. A series of improvement methods are proposed: nonlinear processing at timedomain; windowed filtering at frequencydomain; simplification method of judging voiceless and voiced speech. The experimental results based on MATLAT show that the improved method detects pitch trajectory more clearly and accurately than the AMDF method and the PSR method.