共查询到20条相似文献,搜索用时 78 毫秒
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数字音频压缩(AC-3)(五)(摘译)7.2比特指派7.2.1概述比特指派程序对在进行编码的音频信号,从掩盖效应分析它的频谱包络,以确定将需要的比特数分派给各变换系数的尾数。在编码器中,把所有声道作为一个整体,从一个公共比特区对它实行总的比特指派,没... 相似文献
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20bit K2处理 前面介绍的三种比特扩张技术都是为民用CD播放机开发的.这里介绍的日本JVC公司于1994年发表的20比特K2处理方式则是以业务用CD播放机为主目的开发的。高音质CD的登场是开发该比特扩张技术背景.1993年JVC公司开发出了称之为K2超级编码的高音质比特压缩技术.把用20比特记录的信号变换成16比特.并制作成称之为K2超级编码的CD碟。 相似文献
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在全球导航卫星系统(GNSS)双模接收机的信号捕获过程中,采用"多段匹配滤波器(MMF)+快速傅里叶变换(FFT)"的方式实现信号的时频二维搜索,采用非相干累加算法以提高捕获灵敏度,这2种算法在硬件实现中需要占用大量的存储资源。由于现场可编程门阵列(FPGA)芯片的存储资源有限,本文提出了一种比特压缩方法,极大地降低了非相关累加后的随机存取存储器(RAM)资源,比特重构方法对压缩数据做还原处理,保证了数据的精确度。该方法只对强信号的非相干累加结果做压缩,对弱信号结果不做压缩处理。仿真结果表明,该算法在满足0.9的检测概率,0.01的虚警概率下,节省了0.64 Mbit的RAM资源。 相似文献
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在音频信号降比特技术中,实现数字音频信号的记录和重放的关键技术是码率的压缩。本文介绍音频盒式磁带的精密自适应子频带编码技术和用于数字音频盒式磁带录音机的三片CMOSLSI(MN66701,MN66702,MN66703)和二片BiCMOSIC(AN7630SB,AN7631FHP)。 相似文献
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白1989年索尼公司开始用20比特进行录音以来,相继开发出了几种巧妙地将20比特的数据组合到16比特的CD格式巾去的压缩方法,使CD的音质有所提高,常将这种方式制作的CD称做20比特录音CD。本文将就制作20EL特录音CD的各种比特压缩技术进行介绍。 相似文献
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雷达数据压缩的实验研究 总被引:1,自引:0,他引:1
介绍了一种压缩雷达数据的方法,其主要编码方式是用FFT变换编码和上霍夫曼统计编码。对所采集的雷达数据按不同的量化比特进行了压缩实验,并对数据的压缩性能作了分析。分析表明,量化比特数越大,均 方误差越小;而压缩比越小,压缩速度越快。用户应根据需要选取适当的量化比特数(如8位)。 相似文献
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本文讨论现代雷达中一种具有战术意义的信号——扩展频谱信号(简称扩谱信号),亦即特大时宽、带宽积并且形式多变的脈冲压缩信号。在简单介绍其原理与特征之后,主要讨论该信号的抗积极干扰潛力,最后列举堪称该信号雏形的实例说明其相关接收方法。扩谱信号大大发展了脈冲压缩信号的特点,而其真正实现则依靠采用数字电子技术的崭新分支——频带极宽的,信息率高达每秒千兆比特的电子技术。扩谱信号的产生与处理同计算机相结合可实现同雷达目标环境匹配的自适应接收。 相似文献
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Describes a novel wavelet based audio synthesis and coding method. The method uses optimal adaptive wavelet selection and wavelet coefficients quantization procedures together with a dynamic dictionary approach. The adaptive wavelet transform selection and transform coefficient bit allocation procedures are designed to take advantage of the masking effect in human hearing. They minimize the number of bits required to represent each frame of audio material at a fixed distortion level. The dynamic dictionary greatly reduces statistical redundancies in the audio source. Experiments indicate that the proposed adaptive wavelet selection procedure by itself can achieve almost transparent coding of monophonic compact disk (CD) quality signals (sampled at 44.1 kHz) at bit rates of 64-70 kilobits per second (kb/s). The combined adaptive wavelet selection and dynamic dictionary coding procedures achieve almost transparent coding of monophonic CD quality signals at bit rates of 48-66 kb/s 相似文献
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任意能量有限信号都可以用紧支撑正交小波基展开或分解,这一点对研究快速高效音频编码算法是非常重要的。本文设计一种基于正交小波变换的高保真音频编码算法,该算法可以把速率为705.6kbit/s的高保真音频信号压缩到192kbit/s,160kbit/s,128kbit/s,96kbit/s和64kbit/s,并保持重构音频信号的高质量。 相似文献
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AlgorithmofAdaptiveBitAlocationWaveletTransformAudioCodingMaHongfeiFanChangxinSongGuoxiang(XidianUniversity,Xi’an71... 相似文献
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A perceptual audio coder, in which each audio segment is
adaptively analyzed using either a sinusoidal or an optimum wavelet basis
according to the time-varying characteristics of the audio signals, has been
constructed. The basis optimization is achieved by a novel switched filter
bank scheme, which switches between a uniform filter bank structure
(discrete cosine transform) and a non-uniform filter bank structure
(discrete wavelet transform). A major artifact of the International
ISO/Moving Pictures Experts Group (MPEG) audio coding standard (MPEG-I
layers 1 and 2) known as pre-echo distortion which uses a uniform filter bank structure for
audio signal analysis, is almost eliminated in the proposed coder. A
perceptual masking model implemented using a high-resolution wavelet packet
filter bank with 27 subbands, closely mimicking the critical bands
of the human auditory system, is employed in this audio coder. The resulting
scheme is a variable bit-rate audio coder, which provides compression ratios
comparable to MPEG-I layers 1 and 2 with almost transparent quality. 相似文献
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N. Ruiz-Reyes M. Rosa-Zurera F. Lopez-Ferreras D. Martnez-Munoz 《Circuits, Systems, and Signal Processing》2003,22(6):537-565
This paper describes a new audio coding scheme based on adaptive wavelet
analysis that provides transparent audio coding for CD-audio signals at low bit rates (≈1.4
bits/sample per channel). A new perceptual cost function is defined to obtain the best
wavelet-packet base for each audio frame. The sharp variations in quantization noise that
appear at the border of the frames are minimized by a novel approach that avoids overlapping.
The proposed coder guarantees high perceptual quality using filters that generate
wavelets of any compact support, because a bit-allocation algorithm that takes into account
the equivalent filter frequency responses of the synthesis filter bank branches is used. 相似文献
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