共查询到20条相似文献,搜索用时 234 毫秒
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1引言
SDR(软件无线电)是对数字化无线电信号用软件技术来处理的无线电。其核心是集中使用宽带A/D、D/A转换器并尽可能靠近天线。无线电功能尽可能通过软件来实现。 相似文献
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一种高效数字信道化接收方法 总被引:1,自引:0,他引:1
宽带数字接收系统需要具有快速截获信号的能力,现有的商用数字信号处理器很难实时处理高速A/D变换器输出的大量数据。本文提出一种高效的结构,综合利用数字滤波器的灵活性和多相滤波的高效性,按照先抽取数据,再低通滤波、混频的顺序,较好地解决了硬件速度和高速数据流不匹配的问题。 相似文献
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任何A/D采样都是从被采样信号原始频谱S(f)到采样信号频谱.S′(f′)的一个映射。文章建立了对任意A/D采样(包括欠采样与过采样)都有效的频谱映射一般公式,提出无混迭带通A/D采样速率fs的2个等效准则,以便在随信号调整fs情况下的应用。给出恒定上不能对变频带信号恒无混迭欠采样的推论。 相似文献
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介绍了D/A转换器AD9777芯片的功能特点以及系统结构特点,采用FPGA控制AD9777,实现了宽带线性调频信号的产生,最后与采用AD9764实现方法进行了对比。 相似文献
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在雷达宽带接收系统中,数字中频接收采样率的选择要受限于射频系统的整体设计架构,信号处理系统需要的基带信号数据率可能无法通过对采样信号进行整数抽取获得。针对宽带系统采样率高、数字下变频采用并行多相滤波算法结构、基带信号由多个并行支路组成的特点,以及FPGA处理速率的限制,宽带信号分数抽取运算通常只能采用并行多相方式实现。在宽带数字下变频并行多路基带信号的基础上,通过并行多相内插滤波和并行多相抽取滤波算法,不需要提高FPGA的处理时钟,实现对大带宽信号的分数抽取运算。 相似文献
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本文介绍采用A/D转换器和DSP技术实现混频的一种实验方法,文章从频域角度分析与研究A/D转换器的频率变换功能,并采用欠抽样技术(带通采样技术)对高频带通信号进行采样,然后通过DSP软件编程对采样信号进行实时处理与滤波,便得到低频带通信号。与常规电子线路组成的混频器比较,这种基于A/D和DSP技术实现混频的实验结果表明:对一些固定频率的带通信号是可以实现下混频的。 相似文献
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压缩感知理论指出,稀疏信号可以通过以低于奈奎斯特采样的测量数据重建出原始信号。针对高分辨率SAR成像在奈奎斯特理论下所面临的高速A/D采样、大数据量存储、传输等问题挑战。本文提出了一种基于压缩感知理论的多发多收高分辨率SAR二维成像算法。该算法减轻了高分辨率SAR成像的压力,采用压缩感知处理降低了A/D采样速率、数据量... 相似文献
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LIN Jie SHI Guang-ming CHEN Xu-yang ZHANG Li School of Electronic Engineering Xidian University Xi'an China 《中国邮电高校学报(英文版)》2011,18(6):14-21
High-speed high-resolution analog-to-digital(A/D) conversion demanded by ultra wideband(UWB) signal processing is a very challenging problem.This paper proposes a parallel random projection method for UWB signal acquisition.The proposed method can achieve high sampling rate,high resolution and technical feasibility of hardware implementation.In the proposed method,an analog UWB signal is projected over a set of random sign functions.Then the low-rate high-resolution analog-to-digital convertors(ADCs) are us... 相似文献
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《Microwave Theory and Techniques》1983,31(1):2-10
The analog-to-digital converter (A/D) is a critical component of a signal processing system. GHz-rate A/D's will be required in many future systems. While Si bipolar based A/D's can easily meet 4-6-bit resolution requirements, excessive power dissipation (1 W per bit) limits their operation to 100-400-MHz sampling rates. Recently, GaAs MES-FET's have demonstrated high frequency operation with relatively low power dissipation. This paper describes the design of 2- and 3-bit A/D's using GaAs MESFET's. Monolithic integrated A/D circuits were fabricated and successfully operated at gigahertz sampling rates. This sampling rate is the highest reported for any AD technology at room temperature. The power dissipation is 150-200 mW per bit. With further improvements in comparator sensitivity, the design can be extended to 4-bit A/D for GHz rate operation. 相似文献
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《Electron Devices, IEEE Transactions on》1983,30(1):2-10
the analog-to-digital converter (A/D) is a critical component of a signal processing system. GHz-rate A/D's will be required in many future systems. While Si bipolar based A/D's can easily meet 4-6-bit resolution requirements, excessive power dissipation (1 W per bit) limits their operation to 100-400-MHz sampling rates. Recently, GaAs MESFET's have demonstrated high frequency operation with relatively low power dissipation. This paper describes the design of 2- and 3-bit A/D's using GaAs MESFET's. Monolithic integrated A/D circuits were fabricated and successfully operated at gigahertz sampling rates. This sampling rate is the highest reported for any A/D technology at room temperature. The power dissipation is 150-200 mW per bit. With further improvements in comparator sensitivity, the design can be extended to 4-bit A/D for GHz rate operation. 相似文献
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Zhang Lingwen Tan Zhenhui State Key Laboratory of Rail Traffic Control Safety Beijing Jiaotong University Beijing China 《中国通信》2010,7(1):65-72
Ultra-wide-band (UWB) signals are suitable for localization, since their high time resolution can provide precise time of arrival (TOA) estimation. However, one major challenge in UWB signal processing is the requirement of high sampling rate which leads to complicated signal processing and expensive hardware. In this paper, we present a novel UWB signal sampling method called UWB signal sampling via temporal sparsity (USSTS). Its sampling rate is much lower than Nyquist rate. Moreover, it is implemented in one step and no extra processing unit is needed. Simulation results show that USSTS can not recover the signal precisely, but for the use in localization, the accuracy of TOA estimation is the same as that in traditional methods. Therefore, USSTS gives a novel and effective solution for the use of UWB signals in localization. 相似文献