zhaidai

说明：  2. 关于无线信道的多普勒谱，请回答以下问题： (1) 在某些无线信道中，多普勒频移会引起无线信道输出信号的混叠。请描述产生混叠的各种原因； (2) 无线信道中的多普勒谱有一种经典谱(classic spectrum)，请解释产生这种谱形状的机理； (3) 请用Simulink工具编写代码(S-Function方式)，产生一单径瑞利信道，其多普勒谱为经典谱，其中移动速率为120km/h。并请回答：证明自己用计算机产生的经典谱是正确的可能方法。 (On the wireless channel of the Doppler spectrum, please answer the following questions: (1) In some radio channels, the Doppler frequency shift will cause the output signal of the wireless channel aliasing. Please describe the aliasing produced a variety of reasons (2) wireless channel in the Doppler spectrum has a classical spectrum (classic spectrum), please explain the mechanism of produce such spectral shape (3), please use the Simulink tool to write code ( S-Function mode), resulting in a single-path Rayleigh channel, the Doppler spectrum for the classical spectrum, including mobile rate of 120km/h. And requested the answer: that they used computer-generated classical spectrum is the right possible way.)

用matlab仿真零均值高斯白噪声通过低通带通滤波器前后特性，程序完善，结果与理论值非常接近(The zero mean white Gauss noise is simulated by MATLAB, and the program is perfect through the low pass bandpass filter. The result is very close to the theoretical value.)

给出 了 GOLD 码 的 生成 程序以及分析程序，同时 还并 附有详细 注释可以 运行成功(GOLD given code generation procedures and analytical procedures, but also with detailed notes can run successfully)

短波信道watterson模型的建模仿真，已经编译通过。(Watterson HF channel modeling and simulation model has been compiled through.)

PMA规约模拟测试软件。适合初学者使用，包含几个常用规约(PMA Statute of the simulation test software)

（1） 分析QPSK调制、解调原理，并画出其系统框图； （2） 产生等概率且相互独立的二进制序列，作为待传输的信号，并画出其波形； （3） 进行8PSK调制，分别画出I、Q两支路信号经过乘法器后的波形以及8PSK调制波形； （4） 产生均值为0，方差为1的加性高斯随机噪声，画出其时域波形及频谱； （5） 将加性高斯随机噪声作为传输信道的干扰，画出接收端信号的时域图； （6） 进行8PSK解调，输出解码序列，画出解调后信号波形； （7） 计算系统信噪比、传输误码率。((1) analysis of QPSK modulation, demodulation, and draw the system block diagram (2) have equal probability and independent binary sequence as a signal to be transmitted, and draw the waveform and (3) 8PSK modulation, Draw the I, Q two way signal multiplier waveform and 8PSK modulation waveform (4) to produce zero mean and variance of an additive Gaussian random noise, to draw the time-domain waveform and spectrum ( 5) the additive Gaussian random noise interference as a transmission channel, to draw the time-domain diagram of the receiver signal (6) 8PSK demodulator output decoding sequence, draw the demodulation of the signal waveform computing system (7) signal-to-noise ratio, the transmission bit error rate.)

AWGN信道条件下 汉明编码和格雷编码的性能仿真程序(Hamming coding and Gray coding performance simulation program AWGN channel conditions)

LLL格基规约的matlab算法程序，能够实现向量的格基规约(matlab code for LLL lattice reduction)

matlab仿真LDPC码，对采样点数进行PPM编码，此代码加了保护时隙(The LDPC code is simulated by matlab, and the sampling points are encoded by PPM, which adds protection time slot.)

一个新的通信协议，一线通协议模版软件，希望对大家开发有用(A new communication protocol, Link Agreement template software, everyone would like to develop useful)