文档介绍：毕业论文
题目:智能抢答判别系统设计与研究
摘要
随着时代的进步,电子行业的发展,定时器的应用也越来越广泛。但传统的定时器都是使用发条驱动式、电机传动式或电钟式等机械定时器。电子定时器相对产痛定时器来说,体积小、重量轻、造价低、精度高、寿命长、而且安全可靠、调整方便、适于频繁使用。
本设计倒计时数显定时器电路以NE555电路组成的多谐振荡器作时基,虽然时间精度不十分高,但经济适用。
数字显示式倒计数定时器能够使人们随时看到剩余定时时间的多少,这对某些应用具有一定的实用价值。该设计为一位数的数字显示式定时电路,其结构简单,易于制作,而且时基单位可调(即既可以秒为时基单位,又可以分为时基单位)。全电路由可调式时基信号发生器、减计数与显示器和输出信号控制电路等组成。
关键词:电子时钟,数显,定时,NE556,继电器

ABSTRACT
As time advances, the development of the electronics industry, more and more
widespread application of the timer. However, the traditional spring-driven timers are used, or electric motor drive type, and other mechanical bell timer. Relative labor pain timer electronic timer, the small size, light weight, low cost, high precision, long life and safe, reliable, easy to adjust, for frequent use.
The design of digital countdown timer circuit consisting of NE555 multivibrator circuit for time-base, although the time resolution is not very high, but affordable.
Digital Display Type countdown timer will enable people to readily see how much time the remaining time, which some applications have some practical value. The design for the single-digit figures show style timing, its structure is simple, easy to make, and adjustable time base unit (that is either too basic unit of seconds, and can be divided into time base units). Whole circuit consists of adjustable time base signal generator, by counting and display and output signal control circuit.
Keywords: electronic clock, digital display, timing, NE556, relay
                                                     
目录
1 绪论...................................................................1
抢答简介.........................................................1
抢答器意义......................................................1
工作..............................................................1
2 EDA技简介..............................................................2
EDA技术阶段......................................................2
EDA技术