Short-Term Sinusoidal Modeling of an Oriental Music Signal by Using CQT Transform

In this paper, we propose a method for characterizing a musical signal by extracting a set of harmonic descriptors reflecting the maximum information contained in this signal. We focus our study on a signal of oriental music characterized by its richness in tone that can be extended to 1/4 tone, taking into account the frequency and time characteristics of this type of music. To do so, the original signal is slotted and analyzed on a window of short duration. This signal is viewed as the result of a combined modulation of amplitude and frequency. For this result, we apply short-term the non-stationary sinusoidal modeling technique. In each segment, the signal is represented by a set of sinusoids characterized by their intrinsic parameters: amplitudes, frequencies and phases. The modeling approach adopted is closely related to the slot window;therefore great importance is devoted to the study and the choice of the kind of the window and its width. It must be of variable length in order to get better results in the practical implementation of our method. For this purpose, evaluation tests were carried out by synthesizing the signal from the estimated parameters. Interesting results have been identified concerning the comparison of the synthesized signal with the original signal.

基于常量Q变换的音符起始点检测

针对音乐的音阶频率按指数规律分布的特点,提出基于常量Q变换(CQT)的音符起始点检测算法。该算法根据十二平均律的音阶频率分布规律,对音乐信号进行分解,得到一个分音矩阵,利用该分音矩阵生成检测函数,并提取峰值,得到音符起始点向量。实验结果显示,该算法的检测结果要优于2011年MIREX的结果。

晋语张呼片康保方言入声舒化的社会原因初探

晋语是北方官话中特殊的一种,它保留了古代的入声调。但发展到今天,不少的入声调正在消失,喉塞尾脱落,变成了舒声调,即"入声舒化"。入声舒化,有着深刻的社会原因。以康保方言点为例,方言内部、方言与共同语、方言与方言之间的接触,为入声舒化提供了社会条件,而在经济文化不发达的社会环境下,人们求标准、求文雅的心理则推动了入声舒化的进程。

时变单音干扰下GPS系统的性能分析及干扰抑制方法

针对实际系统中干扰源的移动特性,将干扰信道建模为时变瑞利衰落信道,分析了时变单音干扰下多普勒频移对GPS系统性能的影响并推导了误码率公式,提出了一种基于短时傅里叶的自适应时频域干扰抑制算法。该算法首先对接收到的GPS信号进行时频分析,检测出受到干扰的频点,然后设置合理的干扰剔除门限,最后通过自适应二阶IIR格型陷波器将所受干扰的频点剔除。与基于LMS的时域自适应滤波算法进行了对比,实验证明,所提算法对时变单音干扰具有较好的干扰抑制能力。