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101.
介绍了手机短消息的工作模式,结合3GPP协议分析PDU字符串的意义,从而对发送与接收过程中短消息的编解码进行了研究。 相似文献
102.
为减少测试数据存储量。提出了一种省略FDR码前缀的变一变长度压缩码.称之为共前缀连续长度码CPRL(Co—Prefixal Run Length)。压缩过程分两步,先对测试集差分运算.然后采用CPRL码编码差分向量。它的解压体系结构由一个解码器和循环扫描寄存器CSR(Cyclical Scan Register)组成。针对ISCAS-89基准电路硬故障集的实验结果表明,该方法是一种非常高效的压缩方法。 相似文献
103.
基于自由空间光通讯(FSO)技术和OCDMA编码调制技术实现了自由空间语音异地通讯,具有高速高效、抗干扰能力强、保密性好等优点。系统设计采用双CPU结构,主控CPU单元主要实现语音采集、信号编码、数字调制等功能,辅单片机则为FSO关键技术ATP伺服系统的控制核心,论述了设计要点,并给出了测试结果。 相似文献
104.
Marion Jeanne Christine Guillemot Thomas Guionnet Florelle Pauchet 《Signal, Image and Video Processing》2007,1(1):77-87
This paper addresses the problem of error-resilient decoding of bitstreams produced by the CABAC (context-based adaptive binary
arithmetic coding) algorithm used in the H.264 video coding standard. The paper describes a maximum a posteriori (MAP) estimation
algorithm improving the CABAC decoding performances in the presence of transmission errors. Methods improving the re-synchronization
and error detection capabilities of the decoder are then described. A variant of the CABAC algorithm supporting error detection
based on a forbidden interval is presented. The performances of the decoding algorithm are first assessed with theoretical
sources and by considering different binarization codes. They are compared against those obtained with Exp-Golomb codes and
with a transmission chain making use of an error-correcting code. The approach has been integrated in an H.264/MPEG-4 AVC
video coder and decoder. The PSNR gains obtained are discussed. 相似文献
105.
In this paper, a CMOS realization of the current differencing transconductance amplifier (CDTA) is given, which is a newly reported active building block for current-mode signal processing. Current differencing stage of the CDTA element is realized using a differential current-controlled current source and in the output stage, floating current sources are used to convert intermediate voltage of z terminal to output currents. Due to the compactness of the circuit, it is capable of high-frequency operation and suitable for video signal-processing applications. The CDTA element is used in a current-mode anti-aliasing video filter, which is designed using operational simulation of a seventh-order passive elliptic filter, so the resulting active filter has the low sensitivity feature of its passive counterpart. The filter has 0.1 dB maximum pass band ripple as imposed by ITU video anti-aliasing filter standard. SPICE-simulation results of both the CDTA element and the seventh-order elliptic filter are given. Simulation results are found in close agreement with theoretical results. 相似文献
106.
We present the study of angular selectivity for holographic multiplexing based on random phase encoding by a ground glass. The rotational selectivity of the volume hologram is calculated theoretically and coincides with the experimental measurement. By controlling the parameters including rotational center, effective numerical aperture of both volume hologram and the ground glass, we can obtain different rotational selectivity applied to random phase encoding in volume holographic storage. 相似文献
107.
We present two methods of signal deconvolution for systems whose impulse response (wavelet function) can be explicitly determined, and where the goal is to locate short impulses in the presence of strong, reverberation-like interferences.The first method, which we call algebraic deconvolution, differs from other known techniques in two ways: first of all, explicit use of the wavelet function provides more powerful a priori knowledge than the autocorrelation or the power spectrum. Secondly, this method permits to flexibly trade off noise versus resolution.In the second method presented here, we use an analytical model (synthetic wavelet) of the system impulse response to determine an inverse filter.These methods have been developed for video pulse radar signals, and encouraging early results have been obtained. 相似文献
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110.
3维Hilbert空间填充曲线(3D HSFC)的编码和解码效率对空间查询处理、图像处理等领域的应用举足轻重。现有的3维编解码算法独立编解码每一个点,忽略了Hilbert曲线的局部保持特性。为了提高编解码效率,该文设计了高效的3D状态视图,并提出一种新的前缀约简的3D HSFC编码算法(PR-3HE)和前缀约简3D HSFC解码算法(PR-3HD),这两个算法通过公共前缀的定义和识别、公共前缀约简及多种优化技术来最小化需要编码的阶数,从而提高3D HSFC的编解码效率。理论上证明:当编码或解码一个$k$阶的窗体(窗体内总共含有${2^k} \times {2^k} \times {2^k}$个点)时,PR-3HE平均每个点的编码阶数不超过2,PR-3HD平均解码阶数不超过8/7。相对于传统的基于迭代的方法,编解码时间复杂度从$O(k)$降低到了$O(1)$。实验结果表明,该文算法在模拟数据集和真实数据集上的表现显著优于现有算法。 相似文献