Effects on the glottal voice source of vocal loudness variation in untrained female and male voices

Subglottal pressure is one of the main voice control factors, controlling vocal loudness. In this investigation the effects of subglottal pressure variation on the voice source in untrained female and male voices phonating at a low, a middle, and a high fundamental frequency are analyzed. The subjects produced a series of /pae/ syllables at varied degrees of vocal loudness, attempting to keep pitch constant. Subglottal pressure was estimated from the oral pressure during the /p/ occlusion. Ten subglottal pressure values, approximately equidistantly spaced within the pressure range used, were identified, and the voice source of the vowels following these pressure values was analyzed by inverse filtering the airflow signal as captured by a Rothenberg mask. The maximum flow declination rate (MFDR) was found to increase linearly with subglottal pressure, but a given subglottal pressure produced lower values for female than for male voices. The closed quotient increased quickly with subglottal pressure at low pressures and slowly at high pressures, such that the relationship can be approximated by a power function. For a given subglottal pressure value, female voices reached lower values of closed quotient than male voices.     

基于多孔硅反射谱的农药浓度测量研究

根据多孔硅内浸入液体后其有效折射率发生变化,使其光致发光反射谱峰位发生变化的特性,提出了一种利用多孔硅Bragg反射镜的反射谱来测量克百威溶液浓度的新方法.阐述了多孔硅Bragg反射镜测量农药浓度的原理,利用脉冲腐蚀法制备了多孔硅Bragg反射镜,对多孔硅反射镜和它在不同浓度的克百威溶液中进行了实验,获取了它们的反射光...     

基于半波差分谱的语音信号音节切分

根据听觉感知系统对于动态语音特征的响应特点,提出了半波差分港的概念,在此基础上提出了一种简便的音节切分算法,可以将存在大量协同发音现象的连续语音切分成一个个音节。在连续语音上的切分实验结果说明这种切分算法是准确而可靠的.     

Energy spectrum of an electron beam multiply reflected from the target

The effect of inelastically scattered electrons on the pulsed-beam energy spectrum are studied for the case where they hit back the target upon reflection from the accelerating region. The beam is formed in a vacuum diode and transported to the target by the guiding magnetic field. The formulas for the total and differential fluxes of different-order absorbed and backscattered electrons are presented. It is shown that account of multiple electron backscattering gives rise to a considerable change in the behavior of the normalized heat-source function in the target: the energy loss near the surface of the irradiated target increases markedly due to its reduction in the deep layers of the material. High-Current Electronics Institute, the Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 2, pp. 49–53, February, 2000.     

Generation of the vocal tract spectrum from the underlying articulatory mechanism

A method for synthesizing vocal-tract spectra from phoneme sequences by mimicking the speech production process of humans is presented. The model consists of four main processes and is particularly characterized by an adaptive formation of articulatory movements. First, our model determines the time when each phoneme is articulated. Next, it generates articulatory constraints that must be met for the production of each phoneme, and then it generates trajectories of the articulatory movements that satisfy the constraints. Finally, the time sequence of spectra is estimated from the produced articulatory trajectories. The articulatory constraint of each phoneme does not change with the phonemic context, but the contextual variability of speech is reproduced because of the dynamic articulatory model. The accuracy of the synthesis model was evaluated using data collected by the simultaneous measurement of speech and articulatory movements. The accuracy of the phonemic timing estimates were measured and compared the synthesized results to the measured results. Experimental results showed that the model captured the contextual variability of both the articulatory movements and speech acoustics.     

Effects of consonant-vowel intensity ratio on loudness of monosyllabic words

Previous research has suggested that speech loudness is determined primarily by the vowel in consonant-vowel-consonant (CVC) monosyllabic words, and that consonant intensity has a negligible effect. The current study further examines the unique aspects of speech loudness by manipulating consonant-vowel intensity ratios (CVRs), while holding the vowel constant at a comfortable listening level (70 dB), to determine the extent to which vowels and consonants contribute differentially to the loudness of monosyllabic words with voiced and voiceless consonants. The loudness of words edited to have CVRs ranging from -6 to +6?dB was compared to that of standard words with unaltered CVR by 10 normal-hearing listeners in an adaptive procedure. Loudness and overall level as a function of CVR were compared for four CVC word types: both voiceless consonants modified; only initial voiceless consonants modified; both voiced consonants modified; and only initial voiced consonants modified. Results indicate that the loudness of CVC monosyllabic words is not based strictly on the level of the vowel; rather, the overall level of the word and the level of the vowel contribute approximately equally. In addition to furthering the basic understanding of speech perception, the current results may be of value for the coding of loudness by hearing aids and cochlear implants.     

Effect of ambient noise on the vocal output and the preferred listening level of conversational speech

The effect of ambient noise on vocal output and the preferred listening level of conversational speech was investigated under conditions typical of everyday speech communication. For a speaker-listener distance of 1 m, vocal output and the preferred listening level in quiet were both about 50 dB(A). Deviations from this value were observed when the noise level exceeded a level of about 40 dB(A). The regression lines for the data points above this level showed a 3 dB rise for a 10 dB rise in noise level. The experiments further suggest that both speaker and listener (when the latter is able to control the playback level of recorded speech) try to compensate for the noise interference by raising the level of speech in order to keep the (subjective) loudness of speech in noise equal to the loudness of speech in quiet.     

CCD汽车车灯色度测试及其光谱分析方法的研究

一种新型测色系统依据色度学理论和光谱反射比原理 ,采用CCD作为光电转换元件 ,可一次接收汽车车灯光谱对应的电信号 ,实现了光谱的快速分析 ,给出了CCD对汽车车灯颜色测量的光谱分析方法。并通过计算机控制 ,采用高级VB语言编程进行数据采集和数据处理 ,给出了数据采集程序段。使用该系统将标准色卡的测量色度值与其标准色度值比较所得偏差Δx≤ 0 .0 1;Δy≤ 0 .0 1。     

Al/Nb interface study based on the analysis of the energy spectra of reflected electrons

The interface between a Nb layer deposited on an Al layer is studied via comparison of measured and calculated reflected electron energy loss spectra. The interface region analysis is performed after layer-by-layer sputtering of the sample combined with Auger monitoring of its component composition. The elaborated spectrum calculation technique makes it possible to characterize Al and Nb distributions in the interface region with a nanometer resolution. The possibility of determining the number of phases at the Al/Nb interface is discussed.     

Listening difficulty as a subjective measure for evaluation of speech transmission performance in public spaces

Listening difficulty ratings, using words with high word familiarity, are proposed as a new subjective measure for the evaluation of speech transmission in public spaces to provide realistic and objective results. Two listening tests were performed to examine their validity, compared with intelligibility scores. The tests included a reverberant signal and noise as detrimental sounds. The subject was asked to repeat each word and simultaneously to rate the listening difficulty into one of four categories: (1) not difficult, (2) a little difficult, (3) fairly difficult, and (4) extremely difficult. After the tests, the four categories were reclassified into, not difficult [response (1)] and some level of difficulty, (the other 3 responses). Listening difficulty is defined as the percentage of the total number of responses indicating some level of difficulty [i.e. not (1)]. The results of two listening tests demonstrated that listening difficulty ratings can evaluate speech transmission performance more accurately and sensitively than intelligibility scores for sound fields with higher speech transmission performance.     

A statistical study of the analysis of congested spectra by total spectrum fitting

Heavily overlapped, or congested spectra often display much structure but few individual “lines.” Methods have been devised for analyzing such spectra through nonlinear least-squares fitting of the intensity as a function of wavelength or wavenumber. Such total spectrum fitting (TSF) methods are examined statistically for a simple diatomic model and compared with the standard “measure-assign-fit” (MAF) approach in use since the dawn of spectroscopy. Monte Carlo computations on typically 1000 synthetic spectra at a time verify that the predictions of the variance-covariance matrix are reliable under many circumstances. However in regions where the P and R branches double up, the predicted standard errors in the key spectroscopic constants rise sharply and greatly exceed estimates from the Monte Carlo ensemble statistics. In the same regions, the MAF method actually gives better precision. However, for imperfectly overlapped R and P branches, the MAF standard errors are typically three times larger than the TSF values; moreover, the MAF statistical errors are dwarfed by bias. The TSF approach, while clearly superior in these tests, has a practical drawback: it, too, can give significant bias if the spectra are analyzed with an incorrect model, as illustrated here through calculations employing the wrong function to describe the spectral lineshape.