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基于DFRCT滤波器组自适应语音增强算法
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作者 杨桂芹 徐红莉 宁寰宇 《计算机工程与应用》 CSCD 2013年第2期148-151,共4页
提出一种改进的语音增强方法,将带噪语音信号进行子带分解,再对子带信号进行离散分数余弦变换(DFRCT)域滤波,利用了DFRCT良好的正交特性,且自适应滤波采用最小均方(LMS)算法。对滤波后的信号进行DFRCT逆变换得到增强后的子带语音信号,... 提出一种改进的语音增强方法,将带噪语音信号进行子带分解,再对子带信号进行离散分数余弦变换(DFRCT)域滤波,利用了DFRCT良好的正交特性,且自适应滤波采用最小均方(LMS)算法。对滤波后的信号进行DFRCT逆变换得到增强后的子带语音信号,合成增强后的语音信号。仿真结果表明,该算法在减少输入信号自相关程度的基础上,提高了收敛速度,减少了计算时间(约10s),增强后的语音信号的分段信噪比(SegSNR)和PESQ值都有所提高,具有良好的语音增强效果。 展开更多
关键词 离散分数余弦变换 滤波器组 自适应滤波 子带分解 语音增强
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基于离散分数余弦变换的图像加密算法研究 被引量:4
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作者 朱贵良 秦小立 张晓强 《计算机应用研究》 CSCD 北大核心 2011年第11期4338-4340,共3页
为了提高图像加密的效率和安全性,采用态函数线性组合法构造了一种离散分数余弦变换函数,利用其良好的正交性能及具有分数阶参数和周期参数的特点,提出了一种基于离散分数余弦变换的图像加密新方法。该加密算法采用了图像分块(图元)的... 为了提高图像加密的效率和安全性,采用态函数线性组合法构造了一种离散分数余弦变换函数,利用其良好的正交性能及具有分数阶参数和周期参数的特点,提出了一种基于离散分数余弦变换的图像加密新方法。该加密算法采用了图像分块(图元)的方法。将图像分成大小不同的图元,使用离散分数余弦变换对每个图元分别进行行变换和列变换,从而完成对图像的加密。实验结果分析表明,该算法的加密效果、效率和抗穷举攻击能力是令人满意的。 展开更多
关键词 图像加密 加密算法 离散分数余弦变换 分数阶 图元 周期
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A Proposed Orthogonal Chirp Division Multiplexing (OCDM) Multicarrier Transceiver Based on the Discrete Fractional Cosine Transform
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作者 Hani Attar Ahmed Solyman 《Journal of Computer and Communications》 2017年第2期37-47,共11页
Doppler spread is a phenomenon caused by rapid changes in the channel response due to the movement of the transmitter/receiver through a multipath environment, which is also known as a doubly selective channel respons... Doppler spread is a phenomenon caused by rapid changes in the channel response due to the movement of the transmitter/receiver through a multipath environment, which is also known as a doubly selective channel response. In doubly selective fading channel where the channel frequency response is regarded as rapidly time-varying, the inter carrier interference (ICI) occurs mainly because the traditional multicarrier transceivers are incapable to diagonalize the channel matrix. The proposed scenario is for an Orthogonal Chirp Division Multiplexing (OCDM) multicarrier system derived from Discrete Fractional Cosine Transform (DFrCT). The proposed DFrCT-OCDM multicarrier system is proofed to be less signal processing complexity and easier to implement, compared to the traditional Fast Fourier Transform (FFT). Simulation results reveal that the DFrCT provides superior performance reflected the significant improvement in the BitError Rate which reaches to 10 dB, better spectrum efficiency and better energy concentration properties than the conventional FFT. Finally, several equlizers are applied and they all show that the proposed DFrCT-OCDM over performs the other systems with all these equlizers. 展开更多
关键词 DFT dfrct OFDM DOUBLY Selective Channels Doppler SPREAD
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