共查询到17条相似文献,搜索用时 203 毫秒
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数字宽带波束形成的仿真与验证 总被引:1,自引:0,他引:1
提出了宽带恒定束宽响应数字波束形成的整个流程和方法,通过运用数字延时线和Farrow分数延时滤波器相结合的技术对来波信号进行精确的预延时,运用空间重采样法对不同阵元宽带信号各离散频点的加权系数进行了求解,并根据这些加权系数构建了线性相位FIR滤波器来实现该波束形成算法。仿真和分析结果表明整套设计方法正确、实用、有效。 相似文献
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宽带数字波束形成雷达的高精度延时补偿新方法 总被引:1,自引:0,他引:1
采用宽带信号的相控阵雷达可获得很高的距离分辨率,将广泛用于下一代多功能雷达系统中。传统窄带相控阵体制很难解决宽带相控阵雷达的空间色散和孔径渡越问题,尤其在宽带相控阵雷达做宽角扫描时,必须在阵元或子阵间使用精确的时延补偿。文中提出了一种实现高精度宽带相控阵延时补偿的新方法。该方法采用一种有效的可变分数延时滤波器新结构,即泰勒结构。该结构相对于传统的Farrow结构的主要优点是减少了乘法器和加法器的数量,降低了可变延时滤波器系数的计算难度。试验证明,新的方法能实现精确的宽带波束扫描,可应用于接收和发射数字波束形成的工程实现。 相似文献
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提出了一种可变分数延时宽带数字滤波器的优化设计方法,该方法首先采用内插的方法提高采样率,降低信号的归一化带,再采用Farrow结构来实现分数延时,通过抽取,恢复信号的初始采样率.其实现形式采用基于多相滤波的级联结构,使得内插和抽取相互抵消,降低滤波器的阶数,提高运算效率.采用基于FPGA的并行分布式算法,设计利用了器件的结构特点以及与器件特性独立的2种方法,在时域实现了高速、高阶的宽带分数延时滤波器,并在Altera Stratix FPGA上进行了仿真验证,最高工作频率分别为184 MHz和119 MHz. 相似文献
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基于Farrow结构的分数时延滤波器 总被引:1,自引:0,他引:1
在宽带数字阵列雷达的波束形成中,传统的窄带移相方法存在主瓣展宽和扫描不准的情况,为此现阶段多采用实延时(TTD)补偿单元来代替移相器。模拟时延补偿存在诸多缺点,为实现宽带数字阵列各阵元传输时延的精确补偿,引入声纳学中广泛使用的Farrow结构来实现时延滤波器;为降低FPGA资源消耗,引入滤波器的系数求取优化方法;为提高速度,提出了Farrow结构的优化方法。仿真以及实际运行结果都表明了该方法的有效性,与传统移相方法相比,更适用于数字阵列雷达T/R组件。 相似文献
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2010基于Farrow结构的分数时延滤波器 总被引:1,自引:0,他引:1
在宽带数字阵列雷达的波束形成中,传统的窄带移相方法存在主瓣展宽和扫描不准的情况,为此现阶段多采用实延时(TTD)补偿单元来代替移相器.模拟时延补偿存在诸多缺点,为实现宽带数字阵列各阵元传输时延的精确补偿,引入声纳学中广泛使用的Farrow结构来实现时延滤波器;为降低FPGA资源消耗,引入滤波器的系数求取优化方法;为提高速度,提出了Farrow结构的优化方法.仿真以及实际运行结果都表明了该方法的有效性,与传统移相方法相比,更适用于数字阵列雷达T/R组件. 相似文献
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Djordje Babic 《Circuits, Systems, and Signal Processing》2013,32(2):759-780
An efficient implementation for finding digitally the interpolated samples is the Farrow structure. It mimics digitally a hybrid system where a continuous-time (CT) signal is reconstructed using an analog reconstruction filter having a piecewise-polynomial impulse response. The interpolated samples are obtained by sampling reconstructed signal. This paper introduces a generalized design method for polynomial-based interpolation filters and Farrow structure. The proposed method also can be used to calculate the coefficients of Selva interpolator. In this approach, the ideal CT impulse response is truncated by using CT window functions. The obtained windowed impulse response is then approximated using the piecewise Taylor polynomial approximation. Length of the impulse response and degree of the approximating polynomial can be arbitrarily selected, and in this way the transition band width can be controlled. However, if CT fixed-window functions are used, the stopband attenuation is determined by window type and remains approximately constant with increase of length and order of the impulse response. The stopband attenuation can be controlled by using CT dynamic windows such as Kaiser window. The presented windowing design method is an effective tool for calculation of the Farrow structure coefficients, with filter performance that is comparable to the frequency domain design. 相似文献
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A low complexity, low delay reconfigurable digital filter structure for hearing aids is proposed in this paper. The main objective is to match a given human audiogram, with minimum error. The high computational complexity in the conventional uniform and non-uniform filter bank techniques, probes to shift the design paradigm towards variable filter structure. In this paper, Farrow structure based design is used to realize an arbitrary sample rate converter, making use of a differentiator based model, by which the bandwidth can be continuously varied. The proposed design also considers the importance of the power, area, and” delay in such a critical scenario. Exhaustive comparisons are performed with the existing literature on audiogram matching, and our design is very competitive when compared to the designs in the literature, not only with respect to the matching error but also with respect to area, power dissipation, and hardware complexity. 相似文献
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This paper shows that the problem of designing one-dimensional (1-D) variable fractional-delay (VFD) digital filter can be elegantly reduced to the easier subproblems that involve one-dimensional (1-D) constant filter (subfilter) designs and 1-D polynomial approximations. By utilizing the singular value decomposition (SVD) of the variable design specification, we prove that both 1-D constant filters and 1-D polynomials possess either symmetry or anti-symmetry simultaneously. Therefore, a VFD filter can be efficiently obtained by designing 1-D constant filters with symmetrical or antisymmetrical coefficients and performing 1-D symmetrical or antisymmetrical approximations. To perform the weighted-least-squares (WLS) VFD filter design, a new WLS-SVD method is also developed. Moreover, an objective criterion is proposed for selecting appropriate subfilter orders and polynomial degrees. Our computer simulations have shown that the SVD-based design and WLS-SVD design can achieve much higher design accuracy with significantly reduced filter, complexity than the existing WLS design method. Another important part of the paper proposes two new structures for efficiently implementing the resulting VFD filter, which require less computational complexity than the so-called Farrow structure. 相似文献
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提出了一种基于最小相关熵诱导距离(CIM)和Farrow结构的分数时延估计算法。该算法具有较强的抗脉冲噪声的能力,且所需观测数据较少,时延估计结果精度较高。理论分析和仿真实验表明,所提算法的估计精度和抗脉冲噪声性能均优于基于分数低阶统计量的LETDE算法。 相似文献
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Optimal Farrow coefficients for symbol timing recovery 总被引:1,自引:0,他引:1
The Farrow structure provides an efficient way to implement interpolation filters. Such filters are often required in digital modems to allow symbol timing recovery. A method for generating Farrow filter coefficients that minimize the mean square error (MSE) at the symbol decision instants is presented. Minimizing the MSE at the symbol decision instants is nearly equivalent to minimizing the symbol error rate (SER) but is more mathematically convenient. The MSE at times other than the symbol decision instants does not affect the SER and is not considered in the optimization. Example coefficients are tabulated and performance is illustrated using SER results generated by computer simulation 相似文献