PSO

清华大学信号课程第二次实验，内容是基于傅立叶级数的信号分解以及双音频按键音合成(Tsinghua signal course the second experiment, the content is based on the Fourier series of two-tone signal decomposition and synthesis of key tone)

A polyalphabetic cipher is any cipher based on substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case.Polyalphabetic substitution ciphers are useful because the are less easily broken by frequency analysis, however if an attacker knows for instance that the message has a period n, then he simply can individually frequency analyze each cipher alphabet. The number of letters encrypted before a polyalphabetic substitution cipher returns to its first cipher alphabet is called its period. The larger the period, the stronger the cipher. Of course, this method of encryption is certainly not secure by any definition and should not be applied to any real-life scenarios.

有信道编码，调制，信道估计等，光纤陀螺输出误差的allan方差分析，包括主成分分析、因子分析、贝叶斯分析。( Channel coding, modulation, channel estimation, allan FOG output error variance analysis, Including principal component analysis, factor analysis, Bayesian analysis.)

利用matlab语言实现的BP算法，很好用。(Using matlab language implementation of the BP algorithm, it just works.)

分解结构振动模态,识别模态参数，将多自由度振动分解为若干单自由度振动的叠加(structural mode decomposition)

说明：  经典ldpc编译码程序 gallager的博士论文里的部分仿真程序(classic ldpc encryption procedures Gallager doctoral thesis of simulation program)

QPSK modulation in Rayleigh channel

完成M=4的正交信号的数字通信系统的蒙特卡罗仿真。分析其在加性高斯白噪声下误码率与信噪比之间的关系，绘出误码率-信噪比曲线图，并和物理曲线进行比较。(The completion of M = 4 orthogonal signals in Monte Carlo simulation of digital communication systems. Analysis of the additive white Gaussian noise bit error rate and signal to noise ratio under the relationship between the mapped BER- signal to noise ratio curve, and and physical curves for comparison.)

To find the largest fitness value and its location 寻找最大适应性及相应的位置！Population N=50；crossover bits=n/2 (half of bits of an individual) with random locations，mutation bits = 4 种群数 N=50，交换位数= n/2, 即个体位数的一半，且位置随机； 变异位数统一取为4； Nc=20，28，36，44，individuals for crossover(交换的个数)。Nm=1，5，10，15， individuals for mutation(变异的个数)。(To find the largest fitness value and its location to find the location of the maximum adaptability and the corresponding! Population N = 50 crossover bits = n/2 (half of bits of an individual) with random locations, mutation bits = 4 population size N = 50, exchange digits = n/2, ie half of the median individual, and random position variation is taken as unity median 4 Nc = 20,28,36,44, individuals for crossover (exchange number). Nm = 1,5,10,15, individuals for mutation (the number of variations.))

MATLAB 2维小波变换以及S+P讲解和图像去噪 适合开发人员参考应用 包括原始图像和代码及详细讲解(MATLAB 2-dimensional wavelet transform and the S+ P to explain and image denoising applications for developers, including the original image and the reference code and explain in detail)