节拍阈—系统生产能力分析的一个新指标

节拍是生产加工物流系统中常用的一个指标，用来表述系统的生产率。本文在此概念基础上提出了一个新名词-节拍阈，用以反映一个系统或专机设备所能达到的生产能力的上限值，文章论述了节拍阈的概念，该指标不仅用来进行系统生产能力的匹配性分析，还可能用于设计方案的分析评价。     

一种改进的AMDF求取语音基音的方法

文章在已经被广泛运用的平均幅度差函数(AMDF)的基础上,针对其通过求取"第一谷值点"会产生误差,而求取"最小谷值点"会遇到周期增倍等问题,提出了改进的AMDF方法,它通过简单的预测谷值范围、循环AMDF和线性变换等步骤实现了精确的基音检测.实验结果证明:无论是对不同的语音(男、女音),还是在不同的信噪比情况下.其检测结果都优于传统的AMDF法和LV-AMDF法.     

Perception of Pitch and Roughness in Vocal Signals with Subharmonics

Pitch and roughness were rated according to the extent of amplitude modulation (AM) and frequency modulation (FM) of a subharmonic [fundamental frequency (F0)/2]. The objective was to determine the identification boundaries for pitch and roughness and to discover how both kinds of modulation affect these boundaries. Another objective was to judge the reliability between subjects when identifying subharmonic-related pitch and roughness. Three procedures were used: ABX comparisons, method of adjustment, and rating of roughness. Results indicated that the crossover point to the lower pitch (associated with the subharmonic) occurred between 10% and 30% modulation, depending on modulation type and F0. Subjects demonstrated highly variable perceptions of pitch and roughness, with poor intersubject reliability.     

一种语音信号非周期性、周期性及基频检测的改进方法

APP方法可以准确检测语音信号中的非周期性、周期性和基频,是近年提出的一种先进检测新方法,对于语音基础研究和语音技术应用研究有重要作用。APP方法的最大优点是可以同时检测语音信号的基频周期、周期成分和非周期成分的能量比例,而最大缺点是计算代价巨大,运行时间为110倍实时,成为实际应用的最大障碍。该文在深入剖析APP方法的基础上,从原理架构和技术实现两个方面消除不合理的冗余处理,提出新的改进途径,发展成为改进的APP方法,即MAPP方法。MAPP方法不但加强了APP方法处理机制的合理性基础,改善基频检测的准确性和鲁棒性,而且提高计算效率约1个数量级,在CPU时钟频率为1.70GHz和内存为512MB的Pentium 计算机上的运行时间加快到12.3倍实时。     

The Effect of Cricothyroid Muscle Action on the Relation Between Subglottal Pressure and Fundamental Frequency in an In Vivo Canine Model

The relation between subglottal pressure (P_s) and fundamental frequency (F₀) in phonation was investigated with an in vivo canine model. Direct muscle stimulation was used in addition to brain stimulation. This allowed the P_s-F₀ slope to be quantified in terms of cricothyroid muscle activity. Results showed that, for ranges of 0–2 mA constant current stimulation of the cricothyroid muscle, the P_s-F₀ slope ranged from 10 Hz/kPa to 60 Hz/kPa. These results were compared to similar slopes obtained in a previous study on excised larynges in which the vocal fold length was varied instead of cricothyroid activation. A physical interpretation of the P_s-F₀ slope is that the amplitude-to-length ratio of the vocal folds decreases with CT activity, resulting in a smaller time-varying stiffness. In other words, there is less dependence of F₀ on amplitude of vibration when the vocal folds are long instead of short.     

一种特征波提取速率自适应的波形内插语音编码方案

该文提出了一种特征波形提取速率自适应于输入语音帧特性的波形内插编码方案。基于双加权长时预测增益最大原则并利用前向基音判决实现了较为可靠的基音周期估计算法,用基音周期、浊音度和波表面平坦度决定波形提取速率以及SEW(Slowly Evolving Waveform)和REW(Rapidly Evolving Waveform)的更新速率。实验证明,该文提出的波形内插(WI)编码算法相比固定波形提取速率的WI算法在平均码率和计算复杂度上均有一定程度的降低,且合成语音质量明显优于4.8kbps的CELP语音编码算法。     

Mandarin tone recognition based on wavelet transform and hidden Markov modeling

This paper presents a method of tone recognition for Mandarin speech by using combination of wavelet transform and hidden Markov modeling techniques. A pitch detector based on singularity detection and multi-resolution analysis of wavelet transform is employed for estimation of pitch periods, and hidden Markov modeling with partition Gaussian mixtures probability density function is used for the tone recognition. The algorithm can provide recognition accuracy of 97.22% and 94.47% for speaker-dependent and speaker-independent tone recognition, respectively.     

脉冲MPM小型化行波管螺旋线慢波结构的设计和改进

论述了脉冲MPM用小型化行波管慢波结构的计算设计和定型过程。以CAD软件为工具,以实测数据为依据,达到设计预期。     

高性能汉语语音基音周期估计

精确度、连续性和可行性是语音基音分析中必须考虑的三个主要问题,为解决这些问题,本文提出一种新的汉语语音基音周期估计方法,首先,我们通过以ＬＶＡＭＤＦ方法替代ＡＭＤＦ方法获得了更好的基音估计精度和进域分辨度;其次,我们根据汉语语音的特点提出了元音清晰度的概念,在ＬＶＡＭＤＦ和元音清晰度的基础上,本文设计了元音中心定位、基音谐波单周期校正、基音邻近搜索等一系列算法,从而大大提高了汉语语音基音估计的精确     

基于火炮后座模拟试验台的俯仰角度控制

本文介绍了后坐模拟试验台俯仰角度控制系统的设计,给出了具体方案设计和软件设计过程。通过控制步进电机经由变速器实现预定俯仰角度控制,连接在俯仰机构上的光电编码器实现俯仰角度的精确检测,据此实现角度俯仰的精确控制。实验结果显示该方案准确、快速、精度高,完全符合系统要求,具有非常大的实用价值。