数字频率计的设计_数字频率计的原理_vhdl数字频率计

目录引言····································41.1课程设计目的··································41.2课程设计指标··································4第二章 设计方案分析与论证······················52.1基本原理概述··································52.2设计方案分析··································52.3整体方框图分析································6第三章 单元电路设计····························83.1时基电路设计··································83.2整形与放大电路设计····························93.3逻辑控制电路设计······························93.4阀门电路设计·································103.5计数锁存电路设计·····························113.6译码显示电路设计·····························12第四章 频率计数器实物制作·····················134.1 元件清单····································134.2频率计电路原理图·····························144.3频率计电路PCB图·····························164.4频率计作品实物图·····························17第五章 测试结果分析与设计体会·················185.1课程设计结果分析·····························185.2课程设计小结·································19第六章 参考文献·······························20附录一、主要元器件介绍··························211． 555定时器···································212． 锁存器74LS273·······························223. 计数器74LS90································234. 七段显示译码器74LS48························245. 七段数码管显示器·····························266. 双可重触发单稳态触发器74LS123················27第一章 引言数字频率计是一种用数字显示的频率测量仪表，它不仅可以测量正弦信号、方波信号、三角波和尖脉信号的频率，而且还能对其他多种物理量的变化频率进行测量，诸如机械振动次数，物体转动速度，明暗变化的闪光次数，单位时间里经过传送带的产品数量等等，这些物理量的变化情况可以由有关传感器先转变成周期变化的电信号，然后用数字频率计测量单位时间内变化次数，再用数码显示出来。

因此它是一种测量范围较广的通用型数字仪器。该装置运用数字电子技术基础课所学的基本内容，即可完成设计任务。1.1课程设计目的（1）了解数字频率计的构成，理解几种常用集成芯片的工作原理和应用方法。（2）掌握中小规模集成电路设计与制作的方法。（3）进一步培养学生对数字电路的综合应用能力和设计能力（4）通过查阅手册和文献资料设计出一个频率计数器器，培养独立分析和解决实际问题的能力。1.2课程设计指标（1）可测量的频率范围：1～10KHz；（2）可输入的被测信号波形：正弦波、方波及三角波中任一种波形；（3）输入电压幅度：300mv～5V；（4）显示方式：4位LED显示；（5）测量误差≤±0.1%。第二章 设计方案分析与论证2.1基本原理概述本实验要求设计一个简易的频率计，实现对标准的方正弦波，方波和三角波信号进行频率测量，并把测量的结果送到4位7段的数码管显示，所要求测量范围是1Hz~9999KHz。所谓“频率”，就是周期性信号在单位时间（1s）内变化的次数。若在一定时间间隔T内测得这个周期性信号的重复变化次数N，则其频率可表示为???f＝N/T? 整个设计的基本原理就是对1?秒钟之内输入的波形经过放大整形为方波后进行计数，把所得数据保存在计数器里，经过译码器处理之后，然后送往数码管显示。