A/D和D/A转换器模型 对串行和并行输出的8位A/D和D/A转换器进行仿真，转换值范围为0到255，转换采样率为1次/秒。 -A/D and D/A converter model, serial and parallel output of the 8-bit A/D and D/A converter to simulate the conversion values range from 0 to 255, change the sampling rate of 1 times/sec.