用fpga实现的DA转换器，有说明和源码，VDHL文件。

A PLD Based Delta-Sigma DAC

Delta-Sigma modulation is the simple, yet powerful,

technique responsible for the extraordinary

performance and low cost of today s audio CD

players. The simplest Delta-Sigma DAC consists of a

Delta-Sigma modulator and a one bit DAC. Since,

both of these components can be realized using

digital circuits, it is possible to implement a low

precision Delta-Sigma DAC using a PLD.