【正文】 率計(jì)測(cè)量誤差的一個(gè)重要指標(biāo)。精度是指測(cè)量的準(zhǔn)確程度，即儀器的讀數(shù)接近實(shí)際信號(hào)頻率的程度，精度越高測(cè)量越準(zhǔn)確。例如100GHz以上的頻率，在機(jī)動(dòng)車的防撞雷達(dá)和低功率通訊中繼站就需要這種性能的頻率計(jì)。國(guó)際國(guó)內(nèi)通用數(shù)字頻率計(jì)的主要技術(shù)參數(shù)：（1） 足夠?qū)挼臏y(cè)量范圍。其功能進(jìn)一步擴(kuò)大，除了測(cè)量頻率、頻率比、周期、時(shí)間、相位、相位差等基本功能外，還具有自撿、自校、自診斷、數(shù)理統(tǒng)計(jì)、計(jì)算方均根值、數(shù)據(jù)存儲(chǔ)和數(shù)據(jù)通信等功能。因此，在生產(chǎn)過(guò)程中許多物理量，例如溫度、壓力、流量、液位、PH值、振動(dòng)、位移、速度、加速度，乃至各種氣體的百分比成分等均用傳感器轉(zhuǎn)換成信號(hào)頻率，然后用數(shù)字頻率計(jì)來(lái)測(cè)量，以提高精確度。數(shù)字頻率計(jì)可用純硬件實(shí)現(xiàn)法（可選的器件有通用的SSI/MSI/LSI集成電路、專用集成電路、可編程邏輯器件等），也可用純軟件實(shí)現(xiàn)法（可選的平臺(tái)有PC機(jī)、單片機(jī)、DSP器件等）；一般考慮用軟硬件相結(jié)合的實(shí)現(xiàn)法，但是實(shí)現(xiàn)的頻率精度可能沒(méi)有純硬件實(shí)現(xiàn)的精確高。直接數(shù)字式的優(yōu)點(diǎn)電路穩(wěn)定、精度高、容易實(shí)現(xiàn)系列化、小型化、模塊化和工程化。直接式的優(yōu)點(diǎn)是速度快、相位噪聲低，但結(jié)構(gòu)復(fù)雜、雜散多，一般只應(yīng)用在地面雷達(dá)中。在進(jìn)行模擬、數(shù)字電路的設(shè)計(jì)、安裝、調(diào)試過(guò)程中，由于其使用十進(jìn)制數(shù)顯示，測(cè)量迅速，精度高，顯示直觀，所以經(jīng)常要用到數(shù)字頻率計(jì)。它是一種用十進(jìn)制數(shù)字，顯示被測(cè)信號(hào)頻率的數(shù)字測(cè)量?jī)x器。頻率測(cè)試是電子學(xué)中最基本的測(cè)量之一。如果我們能在給定的1s時(shí)間內(nèi)對(duì)信號(hào)波形計(jì)數(shù)，并將計(jì)數(shù)結(jié)果顯示出來(lái)，就能讀取被測(cè)信號(hào)的頻率。其基本原理就是用閘門計(jì)數(shù)的方式測(cè)量脈沖個(gè)數(shù)。頻率計(jì)的硬件電路是用Ptotues繪圖軟件繪制而成，軟件部分的單片機(jī)控制程序，是以KeilC做為開(kāi)發(fā)工具用匯編語(yǔ)言編寫而成，而頻率計(jì)的實(shí)現(xiàn)則是選用Ptotues仿真軟件來(lái)進(jìn)行模擬和測(cè)試。目前,市場(chǎng)上有各種多功能、高精度、高頻率的數(shù)字頻率計(jì),但價(jià)格不菲。隨著微電子技術(shù)和計(jì)算機(jī)技術(shù)的迅速發(fā)展，特別是單片機(jī)的出現(xiàn)和發(fā)展，使傳統(tǒng)的電子側(cè)量?jī)x器在原理、功能、精度及自動(dòng)化水平等方面都發(fā)生了巨大的變化，形成一種完全突破傳統(tǒng)概念的新一代側(cè)量?jī)x器。因此,頻率的測(cè)量就顯得尤為重要，測(cè)頻方法的研究越來(lái)越受到重視?；趩纹瑱C(jī)的脈沖頻率測(cè)量系統(tǒng)的設(shè)計(jì) 院 系： 機(jī)電與自動(dòng)化學(xué)院 專 業(yè) 班：電氣自動(dòng)化技術(shù)1001班 姓 名： 學(xué) 號(hào)： 20102822025 指導(dǎo)教師： 2013年5月基于單片機(jī)的脈沖頻率測(cè)量系統(tǒng)的設(shè)計(jì)Pulse frequency measurement system based on singlechip design摘 要在電子領(lǐng)域內(nèi),頻率是一種最基本的參數(shù),并與其他許多電參量的測(cè)量方案和測(cè)量結(jié)果都有著十分密切的關(guān)系。由于頻率信號(hào)抗干擾能力強(qiáng)、易于傳輸，可以獲得較高的測(cè)量精度。頻率計(jì)作為測(cè)量?jī)x器的一種，常稱為電子計(jì)數(shù)器，它的基本功能是測(cè)量信號(hào)的頻率和周期頻率計(jì)的應(yīng)用范圍很廣,它不僅應(yīng)用于一般的簡(jiǎn)單儀器測(cè)量,而且還廣泛應(yīng)用于教學(xué)、科研、高精度儀器測(cè)量、工業(yè)控制等其它領(lǐng)域。頻率計(jì)廣泛采用了高速集成電路和大規(guī)模集成電路，使儀器在小型化、耗電、可靠性等方面都發(fā)生了重大的變化。為適應(yīng)實(shí)際工作的需要,本次設(shè)計(jì)給出了一種較小規(guī)模和單片機(jī)(AT89C51)相結(jié)合的頻率計(jì)的設(shè)計(jì)方案,不但切實(shí)可行,而且體積小、設(shè)計(jì)簡(jiǎn)單、成本低、精度高、可測(cè)頻帶寬，大大降低了設(shè)計(jì)成本和實(shí)現(xiàn)復(fù)雜度。關(guān)鍵詞：?jiǎn)纹瑱C(jī) AT89C51 頻率計(jì) 匯編語(yǔ)言ABSTRACT In the electronic field, frequency is a kind of most basic parameter, and all there are close relations in the measurement schemes of many other electric parameters and result of measuring. Because the signal antiinterference ability of frequency is strong, easy to transmit, can obtain higher measurement precision. So, the measurement of frequency seems particularly important, the research of the method is being paid attentionto. The Frequency meter, as one kind of the measuring instrument, often called the electronic counter, its basic function is that frequency and application of cycle Frequency meter of measuring the signal are in a very large range, it not only applies to general simple instrument measurement but also apply to other fields such as teaching, scientific research, highaccuracy instrument measuring, industrial control extensively. With the rapid development of microelectric technique and puter technology, especially appearance and development of the onechip puter, the instruments have all changed enormously in such aspects as principle, function, precision and automatic level to enable the traditional electronic side amount, form a kind of side amount instrument of new generation that totally broke through the traditional concept. The Frequency meter has adopted the highspeed integrated circuit and large scale integrated circuit extensively, make the instrument change greatly in such aspects as miniaturize, power consumptive, dependability. At present, there are various digital Frequency meter of multifunction, high precision, high frequency on the market, but the price is high. In order to meet the need of the real work, design and provide one this time The design plan of Frequency meter bining with onechip puter (AT89C51) on a small scale, not only feasible, and small, design simply, with low costs, the precision is high, can examine the bandwidth frequently, have reduced the design cost and realized plexity greatly. The hardware circuit of the Frequency meter is drawing with Ptotues mapping software, the onechip puter control procedure of the software part, regarded KeilC as the developing instrument to write in AssemblyLanguage, but the realization of the Frequency meter was to select to carry on imitating and test with Protues artificial software.KeyWords：single chip puter T89C51 requency meter AssemblyLanguage目 錄摘要 IABSTRACT II緒論 11 方案論證 3 數(shù)字頻率計(jì)測(cè)量方法 3 幾種方案的優(yōu)劣討論 4 本次設(shè)計(jì)采用的方案及選用依據(jù) 52 系統(tǒng)硬件設(shè)計(jì)