全相位FRM陷波原理及其DSP Builder实现

为设计出陷波点可精确控制、具有高陷波深度及低硬件复杂度的陷波器,提出了一种结合频率响应屏蔽（FRM）技术与全相位滤波技术的高效陷波器实现结构.在分析双相移组合全相位陷波器陷波深度不足的基础上,指出原型滤波器和屏蔽滤波器内含的单窗全相位卷积窗是陷波深度得以大幅度增大的根本原因,理论推导出陷波器频率响应表达式,证明了在平移参数λ取非1/2整数倍的情况下,提出的陷波结构无需任何补偿和校正措施,其陷波深度高达约-200,dB.借助Altera开发工具DSP Builder对所提出的陷波结构进行建模、仿真,产生QuartusⅡ能够识别的VHDL源程序,利用ModelSim进行RTL级仿真,综合、适配并下载至FPGA芯片.实验结果验证了设计方法的正确性和实用性.     

用对乙酰基偶氮氯膦（CPApA）－胶束掩蔽－等吸收点光度法测定镍基合金中铈组稀土和稀土总量

本文用同一试剂对乙酰基偶氮氯膦（ＣＰＡｐＡ）分别测定了铈组稀土及铈组稀土和钇的总量。在盐酸介质中，混合表面活性剂氯化十六烷基吡啶（ＣＰＣ）和乳化剂ＯＰ增敏铈组稀土和ＣＰＡｐＡ的反应，而大量钇被胶束掩蔽。表面活性剂不存在时，在铈组稀土和钇的等吸收点（６９２ｍｍ）测定其总量，样品中稀土组成的变化不影响结果。用本法测定了镍基合金中铈组稀土和稀土总量，结果良好。     

Computational models of music perception and cognition II: Domain-specific music processing

In Part I [Purwins H, Herrera P, Grachten M, Hazan A, Marxer R, Serra X. Computational models of music perception and cognition I: The perceptual and cognitive processing chain. Physics of Life Reviews 2008, in press, doi:10.1016/j.plrev.2008.03.004], we addressed the study of cognitive processes that underlie auditory perception of music, and their neural correlates. The aim of the present paper is to summarize empirical findings from music cognition research that are relevant to three prominent music theoretic domains: rhythm, melody, and tonality. Attention is paid to how cognitive processes like category formation, stimulus grouping, and expectation can account for the music theoretic key concepts in these domains, such as beat, meter, voice, consonance. We give an overview of computational models that have been proposed in the literature for a variety of music processing tasks related to rhythm, melody, and tonality. Although the present state-of-the-art in computational modeling of music cognition definitely provides valuable resources for testing specific hypotheses and theories, we observe the need for models that integrate the various aspects of music perception and cognition into a single framework. Such models should be able to account for aspects that until now have only rarely been addressed in computational models of music cognition, like the active nature of perception and the development of cognitive capacities from infancy to adulthood.     

图解法确定掩蔽剂存在下微溶物沉淀的pH值

本文提出的图解法,可极为简便地确定掩蔽剂存在时微溶物开始沉淀及沉淀完全时的pH值,比文献^[1-3]方法易于求解,计算简便。     

高浓度F~--Al~(3+)体系的热力学分析及氟的测定

设定了Visual minteq软件F~--Al~(3+)体系的物种及平衡常数。模拟滴定和实验滴定结果的相似性证明了软件设定的合理。对F-(0.01/0.1 mol/L)-Al~(3+)(0.02 mol/L)-OH-体系的模拟和分析表明,当F与Al摩尔比相差大时,体系平衡物种分布不同,OH-掩蔽铝的机理也不同,但是在p H值11~12铝都被成功掩蔽;不同的反应机理导致F与Al摩尔比大的体系模拟和滴定曲线差别较大。进一步模拟得到了此p H值区间的最大可掩蔽铝浓度。考虑OH-对氟离子电极的影响,最终确定高氟(0.01~0.1 mol/L)高铝体系氟的测定条件:控制p H值为(11.5±0.2),不大于0.02 mol/L的铝。误差分析表明,当电势测定误差较大时,标准曲线法比标准加入法误差小。     

低码率语音编码中感知加权滤波器的一种新型算法

声学心理模型是对人听觉系统生理结构和人耳主观感知特性的数学抽象模型．这种模型已成功运用于宽带音频编码中．首次提出将声学心理模型原理应用于语音编码中感知加权滤波器的设计．通过对ＩＴＵＧ．７２３．１６．３／５．３ｋｂ／ｓ双速率编码算法中感知加权滤波器的改进,编码器的ＭＯＳ分可以改善０．１～０．３,而且新算法所要求的计算量仅比原算法大０．２６ＭＩＰＳ．基于声学心理模型的感知加权滤波器,与现有各类语音编码器中所用的感知加权滤波器相比,有自适应强、更符合人耳听觉特性、主观处理效果更佳的优点．     

A study of auditory responses to transitions of signal frequencies

I.IntrQductionThecomplexsigna1swithcertainmodesoffrcquencyvariation,suchaschirpsignal,andfrcquencycodingsignal,havebecncxtensivelyusedinm0dcrnactivesonardetcc-hons,andthroughcorrespondingmatched-fllteringthcoptima1receptiont0echoescanbepcrformed.l"'lPractical1yasonar0pcratorncedst0direct1ylistcntotheinputechoesinthemeantimcwatchingthescreent0disp1aytheech0esafterprocessing,andthenaconfidentjudgementfortargetappearancccanbemade-Fromtheviewpointofauditorydetection,aninterestingproblemiswhatthed…     

A canonical model for gradient frequency neural networks

We derive a canonical model for gradient frequency neural networks (GFNNs) capable of processing time-varying external stimuli. First, we employ normal form theory to derive a fully expanded model of neural oscillation. Next, we generalize from the single oscillator model to heterogeneous frequency networks with an external input. Finally, we define the GFNN and illustrate nonlinear time-frequency transformation of a time-varying external stimulus. This model facilitates the study of nonlinear time-frequency transformation, a topic of critical importance in auditory signal processing.     

混响感知的听觉心理

综述了中国传媒大学传播声学研究所近年来在混响的主观感知机理上的研究工作和进展,涉及混响感的语意调查与分析,音乐听闻的混响偏爱度实验,混响感的差别阈限,混响感的因素分析,以及混响处理与音乐情感之间的相互影响等研究结果。对混响感知的研究对进一步探究在有界空间中主观听感的生理心理机制是十分有启发的。     

Recommendations for enhancing the role of the auditory modality for processing sonar data

Submarine warfare continues to pose a threat in present-day military operations. Visual displays play a dominant role for operator detection and classification of underwater and surface targets. However, the visual modality is ineffective for the detection of transient signals. In spite of quieter submarines, transient sounds such as hull popping are difficult to disguise, which makes them more likely to be detected via an auditory display. Operators tend to use auditory displays less often because several factors can impede effective aural processing. In this paper, the sonar problem is reviewed followed by some proposed techniques for making more effective use of the auditory modality for the presentation of sonar signals as a means of further improving operator detection and classification of targets. Some recommendations for augmenting the aural presentation of sonar signals over headphones are then discussed. Key research areas include: (1) a reduction of the sound level of the ambient noise in noisy environments should improve the likelihood that the operator will detect weak signals; (2) the provision to replay sound bites of interest and to compare these against a library of known archetypes should lead to increased accuracy in target classification; (3) the ability to present sonar beams in a three-dimensional auditory display where the spatial position of each sonar beam corresponds to the actual position of the source in the ocean should enable the operator to monitor multiple beams and increase his/her situational awareness. Ultimately, the viability of an auditory display is dependent on operator hearing acuity.