普通话单音节词四声的时间频率分析三维语谱图研究

Study of three-dimensional speech chart by time-frequency analysis in Chinese Mandarin Monosyllabic word phonemes

目的用时间频率分析方法观察汉语普通话单音节四声的物理特征。方法借助MATLAB7．0和SigmaPlot9．0等相关软件，对40个普通话单音节四声单词进行时间频率分析，并将其做成三维语谱图进行研究。结果40个单音节词的基频频率均值在220-320Hz，其均值四声之间比较有显著差异。时间频率分析发现，一声的基频频率及强度较恒定；二声随时间变化，各单音节词的FO、F1频率在发音末期向高频方向偏移，部分单音节词的各波强度在发音末期略有下降；三声各单音节词的韵母频率从发音开始从高频渐偏向低频，发音中期开始偏向高频方向，强度变化呈凹形；四声各单音节词的基频及其谐波的频率从发音开始随时间变化由高频逐渐偏向低频方向．强度从发音开始即快速下降直至发音终点。结论通过时间频率分析及三维语谱图观察，我们认为普通话单音节词四声特征主要体现在基频及其谐波的以时间为函数的频率和强度的动态变化。

Objective To investigate the physical characteristic of Chinese Mandarin Monosyllabic word phonemes by the time-frequency analysis. Methods Manufactured and study the three-dimensional speech chart which was on the basic of information of the time-frequency analysis in 40 monosyllabic words with the SigrnaPlot 9.0 and Matlab 7.0 software. Results The mean value of basic frequency in 40 monosyllabic words was between 220 to 320 Hz area, and the mean value of four groups has significant difference by t-test. It is indicated by time-frequency analysis that the characteristics vary according to the tone of monosyllabic words. With the change of time, the various frequencies and its intensity of tone first remain basically unchanged, the curve is horizontal type; the different frequencies of tone second gradually tend to high-frequency direction, the graph is upward-type, additionally, the intensity of some tone drops little; the divers frequencies of tone third firstly deflect to low-frequency areas, then increasingly deviate to high-frequency direction of bias after maintaining a period of time, the figure is v-type, intensity changes are concave-shaped; The various frequencies of tone fourth deviate from high-frequency to low-frequency areas, and its intensity drops sharply, the graph is decreased type. Conclusion Through time-frequency analysis and three-dimensional speech chart observation, we consider that the physical characteristic of Chinese .Mandarin Monosyllabic word phonemes mainly reflects the frequencies and intensity change with time.