基于89C51单片机技术，介绍了一种数字式频率计数器，该频率计具有操作简单方便、响应速度快、体积小等一系列优点。可以及时准确地测量低频信号的频率。-Based on the 89C51 single-chip technology, introduces a digital frequency counter, the frequency meter is simple convenient, fast response, a series of advantages of small size. Can be timely and accurate measurement of the frequency of low-frequency signals.