P_and_S_waves

自己编的welch方法用于功率谱估计的算法代码，希望有用。(Welch their series method for power spectrum estimation algorithm code, I hope useful.)

说明：  《MATLAB时频分析技术及其应用》的MATLAB源码(MATLAB time-frequency analysis and application quot of the MATLAB source code)

digital watermarking matlab GUI code. Wavelet transform dwt in combination with the svd algorithm

SPECFEM2D，模拟二维各向异性粘弹性介质的地震波传播。(SPECFEM2D simulates seismic wave propagation in two-dimensional anisotropic viscoelastic or coupled viscoelastic-acoustic media.)

the matlab code of fading channel

说明：  利用潮位数据计算理论深度基准面，其中各分潮系数需修改(Calculating theoretical depth datum using tidal data)

矩阵变换函数,可通过该函数实现三位是两的绕轴变换(Matrix transformation function, can be accessed through the function of the three two-axis transformation)

一个学习matlab的课件，对于新入门的学习者比较有帮助(Matlab a learning courseware, the new entry for more helpful to learners)

Computational Electromagnetics for RF and Microwave Engineering

介绍了数字通信中的QPSK调制解调的原理，通过用Matlab编写脚本程序对QPSK通信系统的发射和接收过程的具体实现进行模拟仿真，绘出信号在理想信道和加噪信道中模拟传输时的时域图，并对各模块进行了频谱分析，所得到的结果与 理论基本相符，对于理解QPSK系统的性能并在系统的实际应用上作进一步的设计，提供了有效的参考依据。 (The introduction was done with the principle of the QPSK modulation and demodulation in digital communications，a script was written by using Matlab program to CalTy out a simulation of the QPSK communication system．which contains the concrete realization of transmit and receive process．The time-domain diagram is drew separately when the signal transmits in the ideal channel and in the channel with noise，spectral analysis of each module is also done，the results obtained with theoretical results in the main，which provides an effective frame of reference for understanding the performance of QPSK systems，and the practical application in the system to make further designed．)