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matlab code for cdma . dlsa

快速计算菲涅尔衍射光场，将菲涅尔衍射公式转换为快速傅里叶变换FFT，可以直接嵌入程序中使用，对菲涅尔计算全息很有用！(Fast calculation of Fresnel diffraction field, Fresnel diffraction formula will convert the fast Fourier transform FFT, can be directly embedded program using the Fresnel CGH is useful! ! !)

Important simulations in digital communication BPSK AWGN+RAY channels.

使用Matlab写的EZW算法，里面有实例 (ezw algorithm, there are examples)

小波包分析提取振动信号中的特征频率，D-S证据理论数据融合，能量熵的计算。( Wavelet packet analysis to extract vibration signal characteristic frequency, D-S evidence theory data fusion, Energy entropy calculation.)

an investigation on use of chaotic sequence in DS-CDMA. The DS-CDMA systems offer physical layer security without the need for a significant increase in computation or power requirements. Nowadays, DSCDMA has been used widely. These systems suffers from multiple access interference because of other users transmitting in the cell, channel inter symbol interference and additive white Gaussian noise. Codes have an effective role in DSCDMA system, so M-sequences; gold sequences have been used as spreading codes in DS-CDMA. These sequences by shift registers and periodic in nature are developed. However, these sequences are not enough and also limit the security. This paper presents an investigation on use of new type of sequences called chaotic sequences for DS-CDMA system. These sequences by chaotic maps are generated.

转载：卷积编码＋维特比译码的matlab程序(Reprinted: convolutional code+ matlab Viterbi decoding process)

Approximate entropy analysis of biological signals of the advantages of time series parameters of the approximate entropy, ApEn describes the application of the medical situation and prospects. Methods: According to the definitions and algorithms, introduced approximate entropy and correlation dimension, fractal dimension

1、 生成多周期线性调频信号，并对其进行频谱分析； 2、 对仿真生成的信号利用两种窗口函数进行STFT变换生成时频分析图(1, to generate multi-cycle chirp signal, and its spectrum analysis 2, the signal generated by the simulation window function using two STFT transform to generate time-frequency analysis chart)

说明：  基于PSO（粒子群算法）的列车速度优化，matlab实现。(Train speed optimization based on PSO (particle swarm optimization) is realized by matlab.)