VHDL语言实现PWM信号，非常方便的使用

直接数字式频率合成器DDS设计、Verilog。 产生的信号可以是正弦波或方波、三角波、锯齿波等，自选。 采用DDS技术，将所需生成的波形写入ROM中，按照相位累加原理合成任意波形。 此方案得到的波形稳定，精度高，产生波形频率范围大，容易产生高频。 本实验在设计的模块中，包含以下功能： （1）通过 freq 信号输入需要的频率的值； （2）通过 wave_sel 信号选择所需的波形； （3）通过 amp_adj 信号选择波形放大的倍数。(DDS design of direct digital frequency synthesizer, Verilog. The generated signal can be sinusoidal or square wave, triangular wave, sawtooth wave and so on, optional. By using DDS technology, the required waveforms are written into ROM, and arbitrary waveforms are synthesized according to the principle of phase accumulation. The waveform obtained by this scheme is stable, accurate and easy to generate high frequency waveform. This experiment includes the following functions in the designed module: (1) Input the required frequency value through freq signal; (2) Choosing the required waveform by wave_sel signal; (3) Select the multiplier of waveform amplification by amp_adj signal.)

信号处理中所用到的matlab程序，包括LFM,NLFM,BPSK,QPSK等等。(Matlab procedures used in signal processing, including LFM, NLFM, BPSK, QPSK, and so on.)

FSK模拟信号源，利用ISE7.1或以上环境打开。(FSK signal simulator.The project can be open in ISE7.1 or upgrade version.)

altera公司飓风四代芯片，LCD屏幕彩条显示，有效实现行、场扫描。练习FPGA驱动VGA或LCD显示的入门程序(Altera hurricane four generation chip, LCD screen color display, the effective realization of line and field scanning.Practice FPGA to drive VGA or LCD display)

VLSI based question set

结合截图，quartus2与ModelSim的联调的详细操作步凑，使初学者迅速上手-Combination of shots, quartus2 with the ModelSim FBI put together a detailed step-by-step operation, so that beginners get started quickly

说明：  用verilog语言实现计算反正切函数，在软件无线电中解调PM/FM中使用的尤为频繁。上传的压缩包是modelsim工程，基于6.5c,里边包含一个完整的PM波产生以及解调过程的matlab文件仿真，并取其中间的I和Q支路做为verilog文件的输入，并将其借条输出与MATLAB实际解调输出作比较。 鉴相器的设计基于CORDIC算法，其精度取决于迭代的深度。由于工程实际运用只需要解调出atan值，并不需要绝对的值，所以并没有给予加权，需要的同学可以自己加上。(Calculated using verilog language arc tangent function, the software radio demodulation PM/FM is particularly used frequently. From the archive is modelsim project, based on 6.5c, inside the PM contains a complete demodulation process of wave generation and simulation matlab file, and whichever is the middle of the I and Q branch verilog file as input, and its IOU demodulated output and actual output of MATLAB for comparison. Phase detector design is based on CORDIC algorithm, its accuracy depends on the iteration depth. As the practical application of engineering demodulated atan value only and does not need absolute value, and there is no weight given to the need of the students can add their own.)

这是Verilog语言的if else 语句的优化，不同的写法，编译出来，结果会有很多不同。请大家自己斟酌。-see the Chinese

用VHDL实现一个四位十进制计数器来进行计数，并且仿真通过-To use VHDL to achieve a 4 decimal counter to count, and the simulation through the

说明：  此程序为调试通过的程序，带有I2C总线功能的程序.(this procedure through the debugging process, with I2C bus function procedures.)