文档介绍：毕业设计说明书
(2010届)
高精度频率计设计
学生姓名
学号
系别信息与电子系
专业班级电子信息工程0601
指导教师
完成日期
高精度频率计的设计
摘要
本文介绍了一种基于单片机的宽范围、高精度、智能化且性价比高的频率计的设计方法。详细的介绍了一种等精度测量的思想,并对系统硬件和软件的具体实现进行了深入的探讨说明。本系统以W78E58单片机为核心控制器件,使用LF353PC运算放大器对信号进行放大,并以TL714CP高速电压比较器进行波形整形,利用CD4518BE构成分频器通道同时结合MC74HC151N数据选择器实现量程的自动切换,最后将测量得到的数据计算后在CM12864-12液晶显示器上显示出来。使用C语言完成软件部分的设计,其中结合了平均滤波等数字信号处理技术和自校准等智能仪器技术;介绍了软件编程思想,给出了程序流程图,并最终完成了PCB电路和样机的制作、调试。经实际测试该样机可支持频率范围1HZ~,方波下最小VPP为20mV;正弦波、三角波下最小VPP为40mV三种类型交流信号的频率检测及显示,%。充分结合利用了单片机的数学运算和控制功能,系统硬件相对简单,软件结构优化,实现了宽范围、高精度、智能化及性价比高的最初设计思想。同时增加了自校准,数据锁存和极限报警等功能特点。最后给出了样机的实际测试数据,对测试结果的误差进行了分析探讨,对本系统设计进行了总结和展望。并附上了电路原理图、PCB电路图、使用说明书和实物图片。
关键词高精度频率计;自校准;平均滤波
DESIGN OF HIGH ACCURACY
FREQUENCY METER
ABSTRACT
This thesis introduces in a design method of frequency meter in the basis of MCU’s wide range, high accuracy, intelligence and high cost , it introduces in detail the idea of equal-precision measurement this system adopts, and it makes a deep research for concrete implementation of system hardware and software. The system takes the single-chip puter W78E58 as the core control device, amplifies the signals by operational amplifiers LF353PC, and shapes waveform with high-speed parator TL714CP, achieves the Range Automatic Switch by the CD4518BE as access channel of frequency divider with bination of data selector MC74HC151N, eventually the data measured displayed in the liquid crystal display CM12864- design of software partially uses C language software with bination of digital signal processing techniques such as average filtering, and the technology of intelligent instrument such as the self-calibration techniques; the thesis introduces the idea of software programming, presents the programming flow chart; finally the PCB circuit and the prototype machine are made out and tested. Having been tested, the prototype supports the detection and display of three types AC signals in the frequency range of 1HZ to HZ. They are