【正文】 管顯示出來。t change hardware electric circuit, carries on various function that the improvement can also raise system further to the number39。Increase to spread a feeling machine in the electric circuit, can also make into a number pulse instrument, account a price machine etc..Therefore the digital cymometer accounts in the diagraph physics to measure aspect applied design is used VHDL the spare part is at CPLD up carry out digital cymometer to account to measure repeatedly system, can show to be measured the frequency of signal with the decimal system figures, can measure the frequency of sine wave, square wave and triangle wave etc. signal, and return an ability as to it39。關鍵詞：FPGA芯片、VHDL語言、數(shù)字頻率計、數(shù)字頻率計原理圖、EDA技術AbstractDigital cymometer is to directly show to be measured a kind of diagraph of signal frequency to equip with the decimal system not only can measure sine wave, square wave, triangle wave, sharp pulse signal and other have a period of the frequency of the signal of characteristic, and can also measure their been refitted, can measure pulse width, make into the number type vein breadth to measure an instrument。在不更改硬件電路的基礎上，對系統(tǒng)進行各種改進還可以進一步提高系統(tǒng)的性能。數(shù)字頻率計是計算機、通訊設備、音頻視頻等科研生產(chǎn)領域不可缺少的測量儀器。本設計用VHDL在CPLD器件上實現(xiàn)數(shù)字頻率計測頻系統(tǒng)，能夠用十進制數(shù)碼顯示被測信號的頻率，能夠測量正弦波、方波和三角波等信號的頻率，而且還能對其他多種物理量進行測量。經(jīng)過改裝，可以測量脈沖寬度，做成數(shù)字式脈寬測量儀；可以測量電容做成數(shù)字式電容測量儀；在電路中增加傳感器，還可以做成數(shù)字脈搏儀、計價器等。摘要 數(shù)字頻率計是直接用十進制數(shù)字來顯示被測信號頻率的一種測量裝置。它不僅可以測量正弦波、方波、三角波、尖脈沖信號和其他具有周期特性的信號的頻率，而且還可以測量它們的周期。因此數(shù)字頻率計在測量物理量方面應用廣泛。具有體積小、可靠性高、功耗低的特點。采用VDHL編程設計實現(xiàn)的數(shù)字頻率計，除被測信號的整形部分、鍵輸入部分和數(shù)碼顯示部分以外，其余全部在一片F(xiàn)PGA芯片上實現(xiàn)，整個系統(tǒng)非常精簡，而且具有靈活的現(xiàn)場可更改性。該數(shù)字頻率計具有高速、精確、可靠、抗干擾性強和現(xiàn)場可編程等優(yōu)點。Can measure electric capacity to make into a number type the electric capacity measure an instrument。s he various physical quantity carry on the physical volume small and dependable sex Gao and achievement to consume a low cymometer is the diagraph instrument of research production realm indispensabilities, such as calculator, munication equipments and audio frequency video frequency...etc..The digital cymometer that adopts VDHL to weave a distance to design a realization accounts, in addition to is measured the orthopedics of signal part, the key importation part and figures show part, rest all in one FPGA realization of chip, the whole system simplifies very much, and has vivid spot to change the foundation that doesn39。s frequency accounts to have high speed, precision, credibility, the anti interference is strong and the spot programmable etc. advantage.Key words： The FPGA chip, VHDL language and digital cymometer, the digital cymometer account principle diagram ,EDA technique目錄引言 1技術性能指標及分工 2第1章 頻率計的設計背景及原理 3 設計背景 3 設計原理 3 頻率計設計原理 3 原理框圖 4 設計思路 5第2章 頻率計測量頻率的層次化設計方案 6 6 7 9 24位鎖存器 11 數(shù)碼管控制器 12 譯碼器 14 16總結 20心得體會 21參考文獻 22附錄 2324引言所謂頻率，就是周期性信號在單位時間（1s）里變化的次數(shù)。根據(jù)數(shù)字頻率計的基本原理，本設計方案分三個模塊來實現(xiàn)其功能，即整個數(shù)字頻率計系統(tǒng)分為時基產(chǎn)生與測頻時序控制電路模塊、待測信號脈沖計數(shù)電路模塊、鎖存與譯碼顯示控制電路模塊等幾個單元，并且分別用VHDL硬件描述語言對其進行編程，實現(xiàn)了控制電路、計數(shù)電路、鎖存與譯碼顯示電路。 2011/06/