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11.
Minjie Xie 《中兴通讯技术(英文版)》2012,(2):25-33
Lattice vector quantization(LVQ) has been used for real-time speech and audio coding systems.Compared with conventional vector quantization,LVQ has two main advantages:It has a simple and fast encoding process,and it significantly reduces the amount of memory required.Therefore,LVQ is suitable for use in low-complexity speech and audio coding.In this paper,we describe the basic concepts of LVQ and its advantages over conventional vector quantization.We also describe some LVQ techniques that have been used in speech and audio coding standards of international standards developing organizations(SDOs). 相似文献
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Headphone rendering of nearby virtual sound sources represents to date an open issue in 3-D audio, due to a number of technical challenges and temporal requirements involved in the measurement of individual Head-Related Transfer Functions (HRTFs). In order to tackle this problem, we propose a filter model of near-field effects based on the Distance Variation Function (Kan et al., 2009). Thanks to its simple structure and low order, the model can be applied to any far-field virtual auditory display to yield a realistic and computationally efficient near-field compensation of spectral and binaural effects. The model is subjectively evaluated in two psychophysical experiments where the relative distance of pairs of virtually rendered sound sources is judged. Results show that even though sound intensity overshadows subtler near-field effects when it is available as a cue for distance, the model is capable of offering relative distance information of near lateral virtual sources when intensity cues are removed. Furthermore, performances of the model in relative distance rendering are compared to those of alternative near-field rendering methods available in the literature. 相似文献
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随着科学技术的飞速发展和靶场信息化建设的需要,靶场声像信息媒体资源的整合被提升了前所未有的高度。靶场的声像信息管理争议媒体资产为中心,向数字化、网络化迈进。主要介绍了靶场媒体资产管理系统的构成和关键技术。展望了媒体资产管理系统的发展趋势,并对现在媒体资产管理系统有待完善的方面提出了几点建议。 相似文献
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传统的音频控制电路测试所采用的系统是一种数模混合测试,此系统涉及模拟信号测试与数字信号测试两个方面,频率覆盖了从Hz到上GHz的范围,但缺乏结构化的可测试性设计,测试时间长也较为昂贵。本文研究引入全新的音频控制电路测试方案,是基于单片机的基础上,利用单片机功能强、集成度高、可靠性高及编程开发灵活等特点,并采用PLC技术和模拟测试系统等方式测试音频控制电路,进一步加深了对模拟电路测试系统的利用率。 相似文献
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MPEG系列标准是计算机多媒体应用比较广泛的国际标准之一,音频编码是这标准中的重要内容.近年来人们对压缩音频数据的研究已经取得了很大的进展,本文对几种MPEG音频编码标准进行了较为详细的分析和比较,并简要介绍了它们主要的应用. 相似文献
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YUYING WU HIROAKI IKEDA HIROFUMI YOSHIDA SHIGENOBU SHINOHARA 《International Journal of Communication Systems》1996,9(1):5-11
This paper describes two types of bidirectional addressed audio signal transmission systems where the square-wave frequency modulation (SWFM) and intensity modulation (IM) are used to obtain the optical SWFM signals generated from LEDs at 850 nm. The first one is an addressed audio signal transmission network of tree structure. The sender and auxiliary receiver in the centre are connected to four terminals, each consisting of a receiver and an auxiliary sender, through pairs of optical fibres and an optical splitter used as an optical signal distributor. The second one is a new type of full-duplex one-to-one communication system. The sender and auxiliary receiver in one terminal are connected to the receiver and auxiliary sender in the other terminal through an optical fibre and a pair of directional couplers. Although LEDs in the second system deliver optical SWFM signals at the same wavelength of 850 nm at the same time, the communications are satisfactory because there is no interference from one LED to the other. In both the first and second experimental systems, the audio signal, address, and SWFM carrier occupy 10 Hz to 20 kHz, 65 kHz to 710 kHz, and 6 MHz, respectively. The SNR and distortion were 62 dB and 0.4 per cent, respectively. 相似文献
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介绍了激光唱机和数字功率放大器等数字音频产品的音频特性及其测量方法,并详细讨论了在测试过程中如何选取和设置带通滤波器、低通滤波器和fs/2带通滤波器。 相似文献