摘要CPLD以其功能强大、编程思路简单，在许多场合中获得了广泛的应用。学习其基本原理、开发其电路和软件有较大的实用价值。频率技术广泛应用于导航、空间技术、通讯、工业生产、交通、科学研究及天文学与计量学中。本文内容是论述一种基于CPLD测量频率的解决方案。60128

首先通过各类参考资料，对CPLD设计方法的进行了解，整合出测频的多种方法并进行比较，选定了多周期同步等精度频率计的设计方法，该方法克服了基于传统频率计的测量精度随被测信号频率的下降而降低的缺点，不但具有较高的测量精度，而且在整个频率区域保持恒定的测试精度。接着，在不更改硬件电路的基础上，熟悉电路板构造，并对电路进行调试。最后，运用Verilog语言进行程序开发，并在Quartus Ⅱ软件中进行程序的编译调试和仿真，得出仿真波形图。

关键词  频率测量   CPLD   等精度

毕业设计说明书（毕业论文）外文摘要

Title   Frequency measurement hardware circuit and software design based on the CPLD                                    

Abstract The complex programmable logic device (CPLD) has been widely used today with a variety of domains for its enhanced features and functionality and simple programming method. So that, there are a lot of treasures in practical  applications to study the CPLD techniques with its fundamental, circuit design and programming. Besides, the frequency techniques has been widely used with navigation, space technology, communication, industrial manufacture, traffic, scientific research, astronomy and metrology. This article mainly expounds an frequency measurement solution based on the CPLD with Verilog HDL.

 The article select the main method as the multi-cycle synchronization frequency measurement with equal-precision technique through realizing and comparing a lot of frequency measurement methods with a lot of references and the character of the CPLD, because this method avoids the accuracy deterioration that take place under some special circumstances and it is not only able to achieve high-accuracy survey but also remain constant of the test precision while the whole frequency domains. At last, implementing the solution through programming with Verilog HDL and compiling , running, debugging and simulation to get the simulation waveform graph with Quartus II.

Keywords  Frequency measurement  CPLD  Verilog  equal-precision

1  绪论 1

1．1  测频方法概述 1

1．2  CPLD发展现状 1

1．3  本文研究背景和主要内容 2

2  方案设计 3

2．1  测量原理 3

2．2  测量方法 13

2．3  方法选择 15

3  软件设计 15

3．1  Altera Quartus Ⅱ概述 15

3．2  Verilog HDL语言概述 15

3．3  单元模块设计 17

3．4  仿真时序图 20

4  硬件设计 21

4．1  Altium Designer概述 21

4．2  硬件电路图 21

4．3  硬件调试