说明：  基于PC的数字电压表设计 本文运用AT89S51和AD678进行A/D转换,根据数据采集的工作原理,设计实现数字电压表,最后完成单片机与PC的数据通信,传送所测量的电压值
(PC-based digital voltmeter design In this paper, AT89S51, and AD678 to A/D conversion, the data collected works, designed to achieve the digital voltage meter to finalize the microcontroller and the PC, data communication, transmission of the measured voltage value)