【正文】
and the signal frequency is 100Hz. Timing system contains the counter, decoder, display. Counter 74 LS160 constituted by the decimal counter the decimal and sexagesimal counter, which uses asynchronous binary. The decoder from 74LS48 constitute display digital tube constitute Cleared, the pause function by the RS flipflop. Its specific process: the 100Hz pulse signal generated by the crystal oscillator and first into the counter, and then the ining decoder, a 4bit signal is converted to 7bit signal of the digital control can be displayed, the result by minute, second, 10 milliseconds turn on the digital display. The stopwatch timing is 59 minutes, seconds, 10 milliseconds is the 150 binary counter, minute and second is the six decimal counter.Keyword:Timing accuracy counter display目 錄一、設(shè)計(jì)任務(wù)與要求 2二、方案設(shè)計(jì)與論證 2三、單元電路設(shè)計(jì)與參數(shù)計(jì)算 41.信號(hào)發(fā)生器單元電路 42.時(shí)鐘分頻計(jì)數(shù)單元電路 63.顯示及譯碼單元電路 114.控制電路 13四、總原理圖及元器件清單 14五、結(jié)論與心得 17六、參考文獻(xiàn) 18一、設(shè)計(jì)任務(wù)與要求用74系列數(shù)字器件設(shè)計(jì)一個(gè)電子秒表,要求:1. 。具體過程為:由晶體震蕩器產(chǎn)生100HZ脈沖信號(hào)先進(jìn)入計(jì)數(shù)器,然后傳入譯碼器,將4位信號(hào)轉(zhuǎn)化為數(shù)碼管可顯示的7位信號(hào),結(jié)果以“分”、“秒”、“10毫秒”依次在數(shù)碼管顯示出來。譯碼器由74LS48構(gòu)成,顯示器由數(shù)碼管構(gòu)成。計(jì)時(shí)系統(tǒng)由計(jì)數(shù)器、譯碼器、顯示器組成。本次實(shí)驗(yàn)所做電子式秒表由信號(hào)發(fā)生系統(tǒng)和計(jì)時(shí)系統(tǒng)構(gòu)成,并具有清零,暫停功能?;跀?shù)字電路電子秒表課程設(shè)計(jì)摘 要 電子秒表是一種用數(shù)字電路技術(shù)實(shí)現(xiàn)時(shí)、分、秒計(jì)時(shí)的裝置,無機(jī)械裝置,具有較長(zhǎng)的使用壽命,因此得到了廣泛的使用。它從原理上講是一種典型的數(shù)字電路,其中包括了組合邏輯電路和時(shí)序電路。由于需要比較穩(wěn)定的信號(hào),所以信號(hào)發(fā)生系統(tǒng)555定時(shí)器與電阻和電容組成的多諧振蕩器構(gòu)成,信號(hào)頻率為100HZ。計(jì)數(shù)器由74 LS160構(gòu)成,由十進(jìn)制計(jì)數(shù)器組成了一百進(jìn)制和六十進(jìn)制計(jì)數(shù)器,采用異步進(jìn)位方式。清零,暫停功能由RS觸發(fā)器構(gòu)成防抖動(dòng)開關(guān)。 “10毫秒”為一百進(jìn)制計(jì)數(shù)器組成,“分”和“秒”為六十進(jìn)制計(jì)數(shù)器組成。2. 。二、方案設(shè)計(jì)與論證電子秒表實(shí)際上是一個(gè)頻率(100HZ)進(jìn)行計(jì)數(shù)的計(jì)數(shù)電路。通常使用石英晶體振蕩器電路構(gòu)成數(shù)字鐘。由圖可見,數(shù)字電子鐘由以下幾部分組成:555振蕩器和分頻器組成的秒脈沖發(fā)生器;秒表控制開關(guān);一百進(jìn)制秒、六十進(jìn)制分計(jì)數(shù)器和六十進(jìn)制秒計(jì)數(shù)器;以及秒、分的譯碼顯示部分等