设计并实现了一种适用于便携式故障诊断系统中的FFT算法，该FFT算法利用外部RAM芯片解决了便携式故障诊断系统中数字处理器在计算大数据量FFT算法时出现的内存不足问题。并对实现该FFT算法系统的硬件组成进行了阐述，给出了该FFT算法的软件流程图和软件设计中的要点。将FFT算法应用在便携式故障诊断系统上能够快速并且精确地计算出故障信号的频率，特别适用于便携式故障诊断系统中大数据量的FFT运算。

A FFT algorithm which is suitable for the portable fault diagnosis system is designed and realized in the paper, the FFT algorithm using the external RAM chip solves the problem that the processor of the portable fault diagnosis system is out of memory when the processer calculates the FFT algorithm with a large amount of data. The hardware components used to implement the FFT algorithm are introduced, and in software design, the software flow and the main points are present. Finally, the FFT algorithm in the paper can quickly and accurately calculate the fault signal’ s frequency and especially suitable for the FFT algo-rithm with large amount of data in the portable fault diagnosis system.

复调制Zoom FFT算法在导弹精确制导、防撞雷达等领域有着广泛的需求，是谱估计理论中的关键技术之一。针对传统Zoom FFT算法运算量大、处理速度低和占用资源大的缺点，提出了一种适合于FPGA实现的Zoom FFT算法结构，该结构利用分布式算法实现抗混叠滤波、利用DDS技术实现数控本振信号的产生、利用基－4蝶形算法实现FFT变换，并对该算法结构用硬件描述语言进行了设计、封装。算法仿真和硬件测试结果表明，基于分布式滤波结构构造的Zoom FFT模块，其细化谱分析的精度高、处理速度快和占用资源少，且参数化设计，能够实现真正意义上的实时谱分析，特别适合于离散密集频谱的细化分析与校正。

The complex modulation Zoom FFT is a key technology in spectral estimator theory,which is widely used in precise guidance of missile and anti?collision radar?Aiming at the drawbacks of the traditional Zoom FFT such as computationally expensive, low?speed and more resources occupied,this paper proposes a new Zoom FFT algorithm structure which is suitable for FPGA implemen?tation?This structure makes use of distributed algorithm to realize the anti?aliasing filtration,generate local oscillating with numerical control by DDS technology,and uses radix-4 butterfly algorithm to realize FFT transformation?This structure is designed and encapsula?ted by hardware description language?The simulation and hardware test results show that this Zoom FFT module based on distributed fil?tering structure has many advantages,such as high precision of zoom spectrum analysis,high processing speed,less resources occupied and parametric design?Besides,this structure can realize a true real?time spe

分析了已有FFT算法在谐波电能计量应用中产生的缺陷,提出了加窗FFT谐波电能计量算法,并给出了基于加窗FFT谐波电能计量算法的基本电能计量参数计算公式。运用Matlab进行了算法仿真,构建了谐波电能计量算法的DSP实验系统,编写了浮点型DSP芯片TMS320F28335主程序流程图及电能计量算法子程序流程图,对本文算法进行了实验验证。结果证明,本文的谐波电能计量算法具有很高的准确度,兼具可行性和实用性。

With the analysis on the defects produced by the application of FFT algorithm in harmonic electric energy metering, a harmonic energy metering algorithm using windowed FFT is proposed, and the calculation formula of basic electric energy measurement based on the algorithm are presented. Matlab is used for algorithm simulation, and the DSP experiment system with the harmonic energy metering algorithm is constructed. Based on floating-point DSP TMS320F28335, Flowcharts of the main program and the subroutine for electric energy metering algorithm are presented, and the proposed algorithm is tested by experiments. Experimental results show that the harmonic energy metering algorithm has high accuracy, feasibility and practicability.

介绍分段谱平均算法、两次FFT矩阵算法+频率细化算法和数字信道化等三种超长FFT等效算法。通过仿真分析得到,两次FFT矩阵方法的检测性能最好,测频精度最差,通过频率细化,虽然使检测能力有所下降,但能够达到很高的测频精度,其复杂度很高;分段谱平均方法原理和实现相对最简单,但其信号检测能力最差;数字信道化方法的信号检测能力相当于两次FFT+频率细化方法,测频精度可以通过设置信道数目进行精确测量,而且实现复杂度相对适中。综合考虑检测性能、计算复杂度和硬件可实现性,数字信道化方法最佳。

This paper introduces three equivalent algorithms of large-size FFT which are the averaging multiple FFT, the twice FFT matrix algorithm plus zoom FFT and the digital channelizing method. By simulation and calculation, we know that the twice FFT matrix algorithm has the best performance of signal detection, but the worst precision of frequency measuring. By plus zoom FFT, the performance of signal detection slightly loses, but the precision of frequency measuring is high, and it is very complex. The theory and realization of the averaging multiple FFT are simple, but the capability of signal detection is the worst. The signal detection performance of digital channelizing method equals to that of the twice FFT matrix algorithm plus zoom FFT. And the digital channelizing method can exactly measure the frequency by setting the number of channels, and its realization complexity is moderate. Integrately considering the signal detection performance, calculation complexity and hardware realiz

在扩频通信系统中,PN码的捕获是系统正常工作的前提。为了进一步实现快速捕获,研究了基于FFT的时频并行捕获算法,利用FFT实现频域并行捕获、利用多通道实现码域并行捕获。理论推导验证了该算法的正确性,分析了该算法捕获精度、捕获速度、实现复杂度以及低通滤波效应。仿真结果进一步验证了该算法捕获的正确性。基于FFT的时频并行捕获算法在不降低精度的前提下,可以有效提高捕获速度。

The acquisition of PN codes plays an important part in the Spread Spectrum Communication Systems .In order to accelerate the procedure of acquisition , we study parallel acquisition algorithm , which concurrently per-forms frequency domain searching with FFT and time domain searching with multi channels .And the theoretical de-duction result validates the correctness .Further analysis on precision, speed, complexity and low-pass effect re-veals the superiority.Finally we demonstrate the feasibility from the aspect of simulation .From the theoretical anal-ysis and simulation verification, we can conclude that the proposed parallel acquisition algorithm can accelerate the acquisition without the sacrifice of precision .