improve PI model

AMI码的功率谱,通过仿真产生AMI码并且绘制其功率谱图。(AMI code power spectrum, generated by simulation AMI code and mapping of its power spectrum.)

说明：  在matlab中产生心电信号的程序。很实用(ECG signals generated in the matlab program. Very practical)

关于matlab产生声音的一小段程序很好玩 其中编写了好几个小程序(Matlab generate sound on a lot of fun in which a short program written several small programs)

灰色预测模型MATLAB程序,Grey forecasting model MATLAB (Grey forecasting model MATLAB )

说明：  Shepp-Logan CT 检测器坏伪像仿真，矫正 (Shepp-Logan CT artifact rebuilt)

这是HEED协议的源代码，根据论文的描述缩写，基本实现了论文的功能，但是有些微小的出入。(HEED protocol source code, according to the paper' s description of abbreviations, the basic functionality of papers, but some minor discrepancies.)

Its matlab code for simulation of cognitive radio.

这是一个（2.1.3）卷积码编码、BSC信道传输、Viterbi译码组成的程序合集，运行main.m即可得到仿真结果(This is a (2.1.3) convolutional code, Viterbi decoding, BSC channel transmission is composed of collection procedures, running main.m can be obtained by the simulation results)

Simulation of Gray coded MQAM in Rayleigh fading

说明：  dsp2407 32点fft asm编写(dsp2407 32-point fft asm prepared)