GPS signal tracking

说明：  ldpc编码，里面有ldpc编码，译码以及一系列的具体说明(ldpc encode,ldpc decode and so on)

三维测量重构系统，实现了重构部分的坐标旋转，把完整图像拼接成功(Reconstruction of three-dimensional measurement system to achieve a reconstruction of part of the coordinate rotation, image stitching to complete successfully)

窗函数进行滤波，使用FIR滤波器进行操作(Window function to filter, use the FIR filter to operate)

1）设计Butterworth型音频抗混叠滤波器； 2）参数： 下通带频率300Hz；上通带频率3400Hz； 下阻带频率280Hz；上阻带频率3600Hz； 通带最大衰减0.3dB； 阻带最小衰减40dB； 3）采用一低通滤波器和一高通滤波器级联； 4）分别确定LPF和HPF的性能指标； 5）求出两滤波器的系统函数和频率响应，并画出其幅频特性曲线； 6）求整个滤波器的系统函数和频率响应，并画出其幅频特性曲线。(1) the design of Butterworth-type audio anti-aliasing filter 2) parameters: passband frequency of 300Hz on pass-band frequency 3400Hz under the stop-band frequency of 280Hz on stop-band frequency 3600Hz passband maximum attenuation of 0.3dB minimum stopband attenuation of 40dB 3) the use of a low-pass filter and a high-pass filter cascade 4) separately to determine the performance of LPF and HPF target 5) to derive two-filter system function and frequency response, and draw its increase frequency characteristic curve 6) for the entire filter system function and frequency response, and draw its amplitude-frequency characteristic curve.)

cma dd lms algorithm

LDPC码不同迭代次数对比。码长512，码率1/2，迭代次数分别为0，5，10，50，100.(The LDPC codes different number of iterations contrast. Long code 512, code rate 1/2, the number of iterations were 0,5,10,50,100.)

通信基本仿真3,适合初学者学习的代码,包括了调制,分析等等:使用IIR filter的经典模拟滤波器（巴特沃斯Butterworth,切比雪夫Chebyshev）,Bartlett周期图谱，加窗Bartlett周期图谱，基带波形仿真，IIR的贝塞尔滤波器Bessel Filter，二进制对称信道Binary Symmetric Channel仿真，比特序列，Remez滤波，BPSK复合基带信号仿真，载波生成器，椭圆滤波器Elliptical Filter，FFT,FSK调制及解调，高斯噪声Gaussian仿真，直方图，理想AM，线性PLL，BP混淆器，理想MPSK，正交振幅调变（QAM，Quadrature Amplitude Modulation），正交相移键控(QPSK)，Rayleigh Noise瑞利噪声，Yule-Walker Psd功率谱密度函数。(matlab simulte)

一个相对完整的OFDM通信系统的仿真设计，包括编码，调制，IFFT，上下变频，高斯信道建模，FFT，PAPR抑制，各种同步，解调和解码等模块，并统括系统性能的仿真验证了系统设计的可靠性。(OFDM： coding modulation IFFT AWGN Mode FFT ……)

matlab程序，标准IEEE33节点系统潮流计算程序。(Matlab program, standard IEEE33 node system power flow calculation program.)

说明：  传统的高分辨波达方向（DOA）估计算法中，一般都假设信号位于远场，此时入射到阵列的信源波前为平面波前，空间信号的定位参数可由DOA来确定。然而，当信源处于阵列的Fresnel区域时，信号波前需用球面波来描述，每个信源的定位信息要用DOA和距离联合描述。因此，远场情况下的一些线性理论推导已不再成立，传统的远场算法的估计不再适用(In traditional high resolution direction of arrival (DOA) estimation algorithms, it is generally assumed that the signal is located in the far field, where the source wavefront incident to the array is plane wavefront, and the location parameters of the spatial signal can be determined by DOA. However, when the source is in the Fresnel region of the array, the wavefront of the signal needs to be described by spherical wave, and the location information of each source needs to be described by DOA and distance. Therefore, some linear theoretical deductions are no longer valid in the far-field case, and the estimation of the traditional far-field algorithm is no longer applicable.)