Virtual Sound Intensity Analyzer

The Virtual Sound Intensity Analyzer is a new instrument which has more advantages than the traditional Sound Analyzer. This Analyzer is based on fast Fourie transformation and virtual instrument technique.As an application, combining software and hardware, all kinds of weight noise sound level measurement and real-time noise octave analyzes realized synchronously. The design method has been introduced from three ways, which includes hardware, software and panel. An applied example and error analyze of Virtual Sound Intensity Analyzer are given.This Analyzer is low cost, small volume. and it is also easy to operate. It can be widely used in actual applications.     

基于LabVIEW的农网谐波监测平台设计与开发

针对农村电网谐波源的复杂特性,设计了基于LabVIEW技术的、开放式的农网谐波监测平台,该平台既可以通过高速数据采集卡获取实际电网或标准谐波源中的谐波信号,也可以加载基于LabView或Matlab仿真生成的任意组合的虚拟谐波信号。集成了FFT等多种信号处理方法,用于谐波信号的检测与分析。仿真算例表明,运用基于汉宁窗的FFT方法检测农网常见谐波,可以获得较理想的结果。     

一种高动态环境下的GPS信号捕获方法

本文针对高速运动载体上GPS接收机信号的多普勒频移现象可能导致GPS信号捕获困难的问题,提出了一种基于FFT技术的GPS信号快速捕获方法,有效解决了高速运动载体上GPS信号的快速、稳定接收问题。实验结果表明,该方法是可行的。     

圆锯片适张度量化分析方法的研究

从研究、选取表征锯片适张状态主要指标——适张度的特征参量入手，研究开发了一种以８０３１单片机为主体，以基２复序列ＦＦＴ算法为核心的锯片适张度检测系统。运用该系统对国内外几十种不同规格锯片的实测结果表明，该方法及研制开发的检测系统运用于工业现场是切实可行的。     

Analysis of Wood Anatomy Characteristics by Fast Fourier Transfer Image Analysis

ApplicationofFFTCOlllpLlteril11ageprocessi11gisal1ex`tecI1noIog}'wI1ichmerges0ptics.electro11ics-cOI11l,uteral1dpatter11recog-[lition.ltI1asbeenappIiedt`ideI}intI1cresearcl1of`voodsciencebecauSeitl1asthepropertiesofI1igI1nleasIIri11gspeed.I1igl1precisio11…     

Musical Note Recognition with DWT and FFT

The sole note is a regular cyclical signal. The best frequency domain resolution can be gotten with FFT. However, the harmonic components of the note are extremely rich, so FFT is unable to examine the fundamental frequency accurately. DWT can decompose the signal to low pass rapidly,and has a smooth low frequency approximation. This article brings forward DWT and FFT union musical note recognition method, which realizes the precise frequency recognition of the musical note and is an expected method.     

基于小波去噪的加窗FFT电网谐波检测

提出一种基于小波去噪的软硬阈值改良折衷法与加布莱克曼窗的傅里叶变换算法相结合的谐波检测方法。该方法采用小波软硬阈值改良折衷法对含噪的电力谐波信号进行降噪处理,利用加布莱克曼窗的傅里叶变换算法对去噪后的信号进行分析,提取各次谐波的幅值和频率。仿真检测结果表明小波去噪后的谐波波形接近于原始信号谐波波形,信噪比提高了8.3226dB,小波去噪与FFT 结合的方法适合在谐波检测系统或装置中应用。     

Hyperthyroid Heart Rate Varialility Signal Using Modern Spectrum Analysis Method

Using studied ECG sampling system, the analog signals of electrocardiograph is magnified and filtered,sending into the sampling card in computer, the sampling frequence is 1 000 Hz, the 5 minutes sampling signal is saved to hard disk. Using modern spectrum analysis method and FFT, the specific value VLF/HF of Heart Rate Variability (HRV)of 19 healthy individuals and 10 hyperthyroid is analysed .It is found that the significant difference of the specific value VLF/HF between the healthy individuals and hyperthyroid.There are no especial advantage and distinctness by using the modern spectrum analysis method or FFT to study balance the specific value VLF/HF between the healthy individuals and hyperthyroid. The result shows that the spectrum analysis method is relly an effective measure to analyze independence nerve abnormalities of hyperthyroid.     

基于TMS320F2812的频谱相位校正方法

针对FFT相位误差,从理论上推导出相位的校正公式,并以TMS320F2812 DSP作为系统的控制和处理核心,将DSP运算得到的数据经过RS232串口送至PC比较校正前后结果,通过实例验证了算法的有效性.     

傅立叶变换图像处理方法在木材解剖特征研究上的应用

快速傅立叶变换（ＦＦＴ）图像处理方法是近几年来应用于木材解剖特征研究上的一种先进技术。木材横切面细胞排列具有显著的规律性和周期性,用ＦＦＴ方法得到的ＦＦＴ图谱可以将这些周期性的特征量化提取出来,以便于定量地比较、识别和分类等。因此,木材解剖特征ＦＦＴ图谱的研究对于木材的鉴别、分类及演化规律的研究都具有十分重要的意义。本文总结了ＦＦＴ方法在木材科学领域中的应用,并简要介绍了ＦＦＴ用于木材解剖研究的一般方法。