基于DDS原理，利用VHDL语言进行正弦波、三角波、锯齿波、矩形波等波形的发生。包括完整代码和QUARTUS II工程。-Based on DDS principle, the use of VHDL, sine, triangle, sawtooth, square wave waveform occurs. Including the complete code and QUARTUS II project.

这是用VHDL语言写的数字下变频模块，包含整个工程文件，数字下变频是软件无线电中的关键技术，可以直接用Quartus II打开。-this is a module of DDC(Digital Down Converter) with VHDL, it includes the whole project,you can open it with Quartus II directly.