数值方程组的解

DFT进行频谱分析时的三种现象 1、混叠：对连续信号采样，要求连续信号是带限的，采样频率要足够高。Fs应满足Nyquist采样定理才不产生混叠。 采样前加低通滤波器防混叠 2、频谱泄漏：DFT对时域信号进行了截断（相当于采样信号乘了一个窗函数），时域的乘积相当于频域卷积，改变了原信号频谱。 改用其他窗函数（非矩形）改善泄漏。 3、栅栏现象：DFT 只给出了频谱在采样点上的取值，采样点间的频谱内容丢失。(DFT spectrum analysis of a three phenomena, aliasing : continuous signal sampling, requiring continuous signal is band-limited, the sampling frequency should be high enough. Fs meet the Nyquist Sampling Theorem would not have aliasing. Sampling former low-pass filter plus anti-aliasing 2, spectrum leakage : DFT right time domain signal a disconnect (equivalent to a sampling signal by a window function). time domain is equivalent to the product of frequency-domain convolution, changes in the spectrum of the original signal. Window functions to switch to other (non-rectangular) to improve leakage. 3, fenced phenomenon : DFT spectrum is given only at the sampling point value, sampling points of the spectrum as lost.)

matlab源程序 很有用的 你们可以试用一下(matlab source code useful you can try)

Vector Templates for Handprinted Symbol Recognition

FUZZY logic controller toolbox in Simulink

结构力学连续梁节点弯矩求解，用于求解静定或者超静定梁的内力。(Structural Mechanics continuous beam bending moment for solving the node for the solution of statically determinate or statically indeterminate beam internal forces.)

UNIFAC活度系数模型，该模型公式下标极尽复杂，非常容易出错，在这里很大家共享一下。(UNIFAC activity coefficient model, the model complex formula subscript his best, very easy to make mistakes, here are all to share it.)

this provides the Discrete Fourier Transform function that can be used im more applications

多载波系统中的交调失真，输入信号是频率在11Hz和 14Hz的双音带通信号。(Multicarrier system intermodulation distortion, the input signal is frequency 11Hz and 14Hz dual tape communication number.)

time variable problem using MATLAB

matlab_fuzzymeasure fuzzymeasure