说明：  在电子技术中，频率是最基本的参数之一，又与许多电参量的测量方案、测量结果都有十分密切的关系，因此频率的测量就显得更为重要。测量频率的方法有多种,其中电子计数器测量频率具有精度高、使用方便、测量迅速，以及便于实现测量过程自动化等优点，是频率测量的重要手段之一。在本次毕业设计中我们选择使用单片机来制作数字频率计，并在实际制作中采用了直接测频法。利用延时产生的时基门控信号来控制闸门，通过在单位时间内计数器记录下的脉冲个数计算出输入信号的频率，最终送入LCD中显示。这样制作出来的频率计不仅可以满足设计题目的参数要求，而且具有了单片机的稳定性和成熟性，且控制能力强，是一种低成本，高可靠的设计方案。
(In electronic technology, the frequency is one of the most basic parameters, but also with a number of electrical parameters of the measurement program, the measurement results have a very close relationship between the frequency of measurement, therefore it is even more important. Measurement of the frequency of a number of means, electronic measurement of the frequency counter with high precision, easy to use, rapid measurement, and measurement is easy to realize the advantages of process automation is an important means of measuring the frequency of one. Graduates in this design we have chosen to make use of single-chip digital frequency meter, and used in the actual production of a direct frequency measurement method. Delay arising from the use of gated time-base signal to control the gate time in units of the pulse counter to record the number of calculated frequency of the input signal, and ultimately into the LCD display. This produced not only the frequency of the parameters to)