基于MCS-51单片机的高精度数字测相装置的设计

文档编号:JD615  文档字数:17052,页数:50

中文摘要
相位的测量在自动控制以及通讯电子等领域有着广泛的应用。
    目前常用的相位测量方法，是对两个输入信号进行调理，再通用过零检测的方法使其变换成两个方波。然后将这两个方波进行“与”操作，得到鉴相方波。再由鉴相方波来控制计数器的开停，即用高频脉冲去填充两个信号的相位差，从而实现相位差的测量。但是由于计数方法本身的误差，在测量精度要求比较高或是在鉴相脉宽小于用于计数的时钟脉冲周期时，原来的测量方法就无法满足实际的测量要求。
    本文在对几个常用的测量方法进行简要的分析后，提出了在包含相位差的被测信号多个周期内重复计数，同时在相同个数的原始被测信号周期内进行计数，两个计数结果相减便得到多个鉴相脉宽的计数结果。鉴相脉宽内的计数结果与原始信号周期内的计数结果的比值，即是鉴相脉宽与被测信号周期脉宽的比值，从而计算出相位差的测量方法。
    在测量系统的计数功能模块中，我们选择CPLD器件作为计数处理电路，它使得系统性能大幅度提高，能够满足较高要求的测试。实验证明这种方法测量得到的相位差精确，电路实现简单。

关键词:测相仪，相位测量，相位差

Disgn of Precision Measurement of Phase
Abstract
It is used widely in automation and communication domain.
    The common way of measurement is change the input signal into rectangle waveform after modulation and pass-zero detection. The "and" operation of two input rectangle waveform will bring the phase difference pulse. We use this pulse as the control of counter. It means we take count of clock pulse during the phase difference pulse and get the phase difference later. But errors lies in the way of counter lead the bad measurement, especially when it needs high precision or the clock pulse is wider than the difference.
    After sample analyzing several common measure ways, it brings up counting repeatedly during multiple signal periods including the time delay of two signals and not in different circuit at the same time厂The difference of two counters is the number of clock pulse in time delay. And the ratio of the number of clock pulse in delay time and the number in signal period is the ratio of delay time and the signal period. It can get the phase difference from the ratio.
    We choose the CPLD as the processor in counting system. And it makes the capability of system is much higher than singlechip system. It meets the need of our measure system. It is validated in our lab test that it is a very efficient and simple project of exact phase difference measurement.

Key words: measuring phase instrument,phase measure，phase difference

目    录
插图清单 IV
引  言 V
第一章  绪论 - 1 -
1.1课题的意义 - 1 -
1.2国内相位差测量研究现状概述 - 1 -
1.3课题完成的主要任务和特点 - 2 -
第二章 方案论证 - 3 -
2.1测量原理 - 3 -
2.2方案比较 - 4 -
第三章 单片机系统方案实现 - 8 -
3.1原始信号处理电路 - 8 -
3.2鉴相电路 - 12 -
3.3采样电路 - 16 -
3.4计数及结果采集电路 - 19 -
3.5 显示及键盘控制电路 - 22 -
3.6程序实现 - 25 -
第四章理论计算及精度误差分析 - 27 -
4.1理论计算 - 27 -
4.2精度分析 - 28 -
4.3误差分析 - 28 -
结论与展望 - 31 -
致  谢 - 32 -
参考文献 - 33 -

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