智能频率计的研究与设计

Research and Design of Intelligent Frequency Meter

传统的测量方式采用纯硬件电路进行测量,存在投入成本高、速度慢、占用空间过大等缺点。基于单片机的频率测量方式利用单片机内部的定时/计数器完成信号频率的测量,目前主流的频率测量法有测频法和测周法两大类,这两类方法相比于纯硬件电路测频更加节约成本、节省空间,并且测量速度更快。二者均由简单的频率定义设计,理论上存在一定误差,不能完成高精度测量,且测频法适用于较高频率的测量,测周法适用于较低频率的测量。为扩大测量范围并提高检测精度,本文设计采用传统的51单片机,在测频法和测周法的基础上结合多周期同步测频法,使信号通过特定分频控制模块,由频率计选择合适的量程,在信号输入端添加信号整形模块,将正弦波和三角波转换为方波,方便单片机识别。本设计相对于其他频率计设计简单、造价低、体积小且拥有较高的精度,可以智能的转换波形,选择合适量程,适用于多种频率测量场景。

The traditional measurement method uses pure hardware circuit to measure,but it has disadvantages such as high input cost,slow speed and excessive space occupation.The frequency measurement method based on single chip microcomputer uses the timing/counter inside the single chip microcomputer to complete the measurement of the signal frequency.At present,the mainstream frequency measurement method has two categories:frequency measurement method and measurement cycle method.These two kinds of methods are more cost saving and space saving than the pure hardware circuit frequency measurement,and the measurement speed is faster.However,both of them are designed by simple frequency definition,so there are certain errors in theory and they cannot complete high-precision measurement.In addition,frequency measurement method is suitable for high frequency measurement,while measurement cycle method is suitable for low frequency measurement.To enlarge the measuring range and improve the detection accuracy,the design adopts traditional 51 single-chip microcomputer,based on the frequency measurement method and measurement cycle method to combine multiple cycle with pacing frequency method in order to make the signal through a particular frequency control module.The design shall be formulated by the software frequency meter to choose the appropriate range,adding the whole form module in the signal input end.The sine wave and triangle wave are converted to a square wave to be convenient for the single-chip computer to recognize.Compared with other frequency meters,this design has the advantages of simple design,low cost,small volume and high precision.The wave form can be intelligently converted and the appropriate range can be selected,which is suitable for a variety of frequency measurement scenarios.