共查询到20条相似文献,搜索用时 31 毫秒
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FIR与IIR频率选择滤波器的设计,被广泛应用于数字信号处理领域之中。文章以雷达回波信号的数字处理为例,首先分别设计FIR,IIR滤波器完成了对信号特定频率分量的滤除。进而,针对IIR滤波器的非线性相位,基于最优化设计全通系统实现了相位补偿,并对FIR,IIR滤波器进行了综合比较。 相似文献
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提出了一种部分补偿Sigma Delta调制器整形噪声的新方案.通过在鉴频鉴相器中的延迟时段向无源滤波器中注入补偿电流,最大可实现16dB的噪声补偿.与其他补偿方案相比,文中提出的方案相对简单和易于实现.特别设计了可变延迟的鉴频鉴相器和补偿电流源,并给出了行为级和电路级的仿真结果. 相似文献
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本文提出用全相位数字滤波器这种新型滤波器滤波白噪声产生有色噪声的方法,这种方法比用传统FIR滤波器产生的有色噪声频谱泄漏少,阻带衰减功率大等优点.并且分别用Welch法和全相位法对在有色噪声中混入的双频小信号余弦波进行谱估计,实验证明全相位谱估计性能优于经典谱估计. 相似文献
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This paper proposes a robust variable step-size adaptive IIR filter realized by a new bias-free structure (BFS). Unlike equation error (EQE) method that uses a desired signal contaminated with observation noise, the BFS employs a filter driven by the output of the plant estimate and this achieves a bias-free estimate of the denominator of the system function. In addition, the adaptation is made robust to the observation noise by the Griffiths’ LMS adaptation, which uses the cross-correlation estimate between the input and the desired signal for its adaptation gradient computation. A robust variable step-size adaptation is also realized by the Griffiths’ gradient. The proposed structure is referred to as BFSGV and has good modeling capability with improved convergence rate and reduced misadjustment. For system identification, the proposed BFSGV algorithm gives a 3 dB improvement in the performance index over EQE method. The proposed BFSGV has been applied to active noise control (ANC). The BSFGV structure is used for secondary path (SP) estimation, and for the main path (MP), BFS structure with step-size varied according to Okello’s method (BSFV) is used. The new ANC system for narrowband noise field is found to be having 4 times faster convergence rate and an additional noise reduction of 15dB over that FIR for MP and the EQE for SP. Further, the use of the proposed ANC IIR algorithm achieves computational savings compared to that of FIR. For the broadband noise field, the proposed method that uses BSFV for MP and BSFGV for SP provides 18 times faster convergence rate and 2.5 dB reduction in ANC error compare to that of the ANC using FIR for MP and the EQE for SP estimation. 相似文献
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Oversampling digital-to-analog (D/A) converters employing sigma-delta modulation noise shaping and single-bit quantization are attractive for use in digital audio applications because of their relaxed reconstruction filtering requirements and their tolerance of component mismatch. However, the use of a two-level D/A interface results in a large amount of out-of-band quantization noise that typically must be attenuated by a carefully designed analog reconstruction filter. This paper introduces a means of simplifying the reconstruction filter design through the use of a semidigital finite-impulse-response (FIR) filter. In particular, it describes an oversampling D/A converter wherein a current-mode semidigital reconstruction filter is used to implement a multilevel D/A interface that attenuates the out-of-band quantization noise without requiring precise component matching. An experimental implementation of the converter achieves a dynamic range of 94 dB and 72 dB attenuation of out-of-band quantization noise for a baseband of 20 kHz. The prototype converter, which consists of a linear interpolator, a second-order noise shaper, and a 128-tap semidigital FIR filter, dissipates 59 mW from a 5-V supply and occupies an active area of 3 mm2 when integrated in a 1.2-μm digital CMOS technology 相似文献
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数字滤波器滤除电子测量系统中工频及其谐波干扰的研究 总被引:3,自引:1,他引:2
在电子测量中工频是主要的噪声干扰源之一,若不滤除将大大影响测量精度。而传统的模拟电路滤波器在精度方面无法与数字滤波器相比;另外对多阻带滤波器的设计摸拟电路更是无法实现。本设计用FIR(Finite Impulse Response)数字滤波原理设计了阻带范围分别为48~52Hz,98~102Hz,148~152Hz的三阻带数字滤波器,经仿真实验证明其对电子测量系统中的工频50Hz及其二次谐波和三次谐波干扰将衰减30dB。对去噪后的信号进行分析,大大提高了测试系统的精度,整个过程分为多阻带滤波器的数学建模和滤波算法实现,并分析比较了不同窗函数和阶数的变化对滤波性能的影响。 相似文献
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Sang Hwan Park Wook Hyun Kwon Oh Kyu Kwon Myung-Joon Kim 《Signal Processing, IEEE Transactions on》1997,45(6):1535-1542
The Fourier coefficients (FCs) of quasiperiodic signals are assumed to be in random walk motion in order to represent a broader class. A state model for such quasiperiodic signals is derived. The optimal short-time estimate of the Fourier coefficients is obtained via the suggested optimal harmonic FIR filter (OHFF) based on this state-space signal model. The optimal harmonic FIR filter can be considered to be a generalization of the discrete Fourier transform (DFT) in the sense that it becomes the same as the DFT when the state model is for periodic signals and the filter length is equal to the order of the state model. The optimal harmonic FIR filter derived from the model, even with nonzero state noise and measurement noise, gives an exact harmonic estimate when an incoming signal is periodic and noiseless. It is shown by examples that the ability to suppress noise and the ability to resolve changes of the Fourier coefficients can be adjusted by the filter length and the noise covariance of the state model. Finally, the suggested scheme is compared with existing short-time Fourier analysis methods in a test signal that has time-varying Fourier coefficients 相似文献
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FIR数字滤波器广泛应用于实时数字信号处理领域.本文介绍了FIR数字滤波器的结构、特点及设计方法,并采用窗函数法设汁了FIR滤波器.利用TMS320VC5509 DSP芯片强大的数字信号处理功能实现了该滤波器.实验表明,此数字滤波器工作稳定,能够满足实时的滤波处理功能. 相似文献
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A digital-to-analog converter (DAC) composed of a cascaded digital /spl Sigma//spl Delta/ modulator and the combination of a semidigital/digital finite-impulse response (FIR) and an infinite-impulse response (IIR)-SC/RC filter is described. The architecture enables the analog linear reconstruction of 16/spl times/ oversampled digital signals. With the analog section implemented in CMOS 0.18-/spl mu/m and the digital part programmed into a field-programmable gate array (FPGA), the modulator plus reconstruction filter achieves a peak SNR of 78 dB. The spurious-free dynamic range reaches 80 dB and stays better than 73 dB within the 1.104-MHz signal band. A missing-tone-power ratio of 70 dB, demonstrated for a signal with 15-dB peak-to-average ratio, proves that the solution is suitable for ADSL-CO transmitters. 相似文献
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Qassim Nasir 《International Journal of Electronics》2016,103(4):736-746
The objective of this work is to analyse the performance of the newly proposed two-tap FIR digital filter-based first-order zero-crossing digital phase-locked loop (ZCDPLL) in the absence or presence of additive white Gaussian noise (AWGN). The introduction of the two-tap FIR digital filter widens the lock range of a ZCDPLL and improves the loop’s operation in the presence of AWGN. The FIR digital filter tap coefficients affect the loop convergence behaviour and appropriate selection of those gains should be taken into consideration. The new proposed loop has wider locking range and faster acquisition time and reduces the phase error variations in the presence of noise. 相似文献
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自干扰消除技术是实现带内全双工(IBFD)通信的重要前提,其中数字域自干扰消除是带内全双工通信系统中硬件复杂度最低、灵活性最高的自干扰消除技术,并且是自干扰消除的最后一道防线。然而,其消除能力仍需提升,主要是如何处理收敛速度和稳态精度之间的平衡,并且还要具备突变信道的自适应能力。文章提出了一种新的全双工系统的数字自干扰消除方法,发射链路采用数字、模拟预失真技术消除功率放大器的非线性失真,使用辅助接收链获取发射链路信号副本,在数字域中利用重构自干扰信号副本消除接收信号残余自干扰信号和功率放大器残余非线性失真,并通过在接收链与辅助接收链之间共用一个振荡器消除部分接收机相位噪声。仿真表明,该方法与已有变步长LMS消除方法相比,在信噪比为5 dB的条件下,能够在提高收敛速度的同时获得优于变步长LMS方法的消除能力。 相似文献
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提出一种子载波演化方法分析基于强度调制直接探测的正交频分复用无源光网络中的非线性。该无源光网络中的非线性主要来源于调制过程中的子载波混合干扰和啁啾。传输过程的光纤色散会导致调制时的各子载波最佳相位匹配条件不能维持,进一步导致信号恶化。设计了一种新的Volterra数字滤波器除信号失真。修正的Volterra数字滤波器不仅包含相同的采样点,还包括了不同的采样点。通过实验验证了该滤波器去除信号失真的效果;在FEC为10-3的情况下,实验结果与已经报道的结果相比提升3 dB了功率效益;传输25 km光纤与背对背相比,FEC为10-3时的功率亏损小于0.5 dB;系统的数据传输速率达到24.5 Gbps,频谱效率达到7 bits/s/Hz。实验结果表明提出的方法可以有效地消除信号的线性和非线性失真,能够有效地恢复信号。 相似文献