功率互补型混合滤波器组设计

【作者】 汤宁生；

【导师】 黄建国；

【作者基本信息】 电子科技大学 ， 检测技术与自动化装置， 2007， 硕士

【摘要】 现代电子战中,数字化技术已经得到了广泛的应用。随着战场信号覆盖的瞬时带宽越来越大,信号实时处理对模拟信号数字化的要求也越来越高。同时,在FPGA等硬件平台高速发展的推动下,数字信号处理的速度有了空前的提升,这也迫切要求ADC系统的速度和精度不断提高。功率互补型混合滤波器组是实现高速高精度数据采集系统的一种有效方法,主要应用于宽带高精度数字化仪等测试仪器。宽带高精度数字化仪要求达到400MSa/s的采样率和12bit的分辨率,然而,由于现有芯片技术的限制,直接用一片ADC尚无法达到该指标,为此采用包含两片ADC的功率互补型混合滤波器组技术实现高速、高精度ADC系统。本文针对上述指标需求,详细地阐述了功率互补型混合滤波器组的设计方法以及相关理论。主要内容为:1.仔细研究了功率互补型混合滤波器组技术以及模数转换系统中信号完全重构的原理。2.详细介绍了遗传算法及其优化工具箱的应用,优化求解三阶模拟分解滤波器的传递函数,在此基础上,利用双端梯形网络技术得出滤波器RLC电路图和元件值。3.阐述了数字综合滤波器优化过程,并以信号的完全重构为依据,确定了理想数字综合滤波器的频率响应;再次利用遗传算法优化工具箱优化系统延时,同时根据反傅立叶变换求解出数字综合滤波器的系数,最后基于并行分布式算法和FPGA设计出数字综合滤波器。设计过程中,经过多次优化和尝试,确定了功率互补型混合滤波器组的设计方法和步骤,最终采用了3阶模拟分解滤波器和29阶数字综合滤波器,所得系统的峰值失真误差为1. 4×10?6dB,平均混叠误差-125dB,满足400MSa/s,12bit采样系统的要求。更多还原

【Abstract】 In today’s electronic war, digital signal processing has been widely used. As the signal in the war field covers the wider instantaneous bandwidth, real-time signal processing shows the higher requirements of converting analog signal to digital signal. Meanwhile, with the promoting of the rapid development of FPGA and other hardware platforms, the speed of digital signal processing gains an unprecedented upgrade. It is also an urgent requirement to improve the speed and resolution of ADC system.Power complementary hybrid filter bank is an efficient method for realizing high speed and high resolution data acquisition system and it is mainly used in wide band and high resolution digitizer and other testing equipments. The wide band and high resolution digitizer demands to achieve 400MSa/s sampling rate and 12-bit resolution. However, due to the constraints of existing chip technique, it is difficult to achieve the target using one piece of ADC directly. Therefore, technology of power complementary hybrid filter bank containing two pieces of ADC is used for this purpose to enable the high speed and high resolution ADC system.This dissertation researches the design method and the associated theory of power complementary hybrid filter bank aiming at the above target. The main contents are as follows:1. Technology of power complementary hybrid filter bank and the theory of completely reconstructing signal in analog/digital conversion system are investigated in detail.2. Genetic Algorithm and application of the Genetic Algorithm Optimization Toolbox is demonstrated, which is developed to optimize the transfer function for third-order analog analysis filters. On this basis, RLC circuits and component values of the analog analysis filters are got according to doubly terminated ladder networks.3. Optimization of the synthesis filters is presented and the frequency responses of the ideal synthesis filters are determined based on the theory of completely reconstructing signal. Genetic Algorithm Optimization Toolbox is introduced again to optimize the system delay. At the same time, according to the Inverse Fast Fourier Transform, the synthesis filters coefficients are obtained. Finally, parallel distributed arithmetic is employed to implement the FIR digital filters in the FPGA.During the design, through a series of optimization and tries, the design methods and steps for the power complementary hybrid filter bank are ascertained. The system adopts three-order analog analysis filters and 29-order synthesis filters, introduces 1. 4×10?6dB peak distortion and -125dB average aliasing error, which can meet the requirements of 400MSa/s sampling rate and 12-bit resolution.更多还原