{"resolved":true,"match_type":"uuid","source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","requested_by":"printed_page","book":{"source_type":"original_book","book_id":"38270854-596f-4a26-8183-db8c968c6020","id":"38270854-596f-4a26-8183-db8c968c6020","uuid":"38270854-596f-4a26-8183-db8c968c6020","title":"编码 隐匿在计算机软硬件背后的语言","normalized_title":"编码隐匿在计算机软硬件背后的语言","author":null,"edition":null,"publisher":null,"year":null,"isbn":"9787121181184","isbns":["9787121181184","0123456789","6044921875","3039331000","0000000000","0000000000000"],"parsed":true,"ai_readable":true,"document_type":"book","page_count":438,"navigation_url":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020","title_url":"https://workshop.closeclaw.top/ai/title/%E7%BC%96%E7%A0%81%20%E9%9A%90%E5%8C%BF%E5%9C%A8%E8%AE%A1%E7%AE%97%E6%9C%BA%E8%BD%AF%E7%A1%AC%E4%BB%B6%E8%83%8C%E5%90%8E%E7%9A%84%E8%AF%AD%E8%A8%80","fixed_page_url_template":"https://workshop.closeclaw.top/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","path_api_url_template":"https://workshop.closeclaw.top/api/ai/book/38270854-596f-4a26-8183-db8c968c6020/page/{printed_page}","read_url":"https://workshop.closeclaw.top/api/ai/read/38270854-596f-4a26-8183-db8c968c6020","page_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/page","search_url":"https://workshop.closeclaw.top/api/ai/books/38270854-596f-4a26-8183-db8c968c6020/search"},"page":{"printed_page":184,"pdf_page":200,"physical_index":200,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"1d79b29c934ca4edce4ee6fc43e593c80a7514ce0d428252700733b0fb1941bf"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"时钟信号的每一个正跳变发生时，一些Q输出可能会改变，而另外一些可能不变，但总体上来说它们所表示的二进制编码递增了1。\n\n本章前面提到过可以找到某种方法来确定振荡器频率，现在已经找到这种方法了。如果把一个振荡器连接到8位计数器的时钟输入端上，那么这个计数器会显示出振荡器经过的循环次数。当计数器总数达到11111111（十进制的255)，它又返回为00000000。使用计数器确定振荡器频率的最简单的方法就是把计数器的8个输出端分别接到8只灯泡上。当所有的输出都是0时（即所有灯泡都是熄灭的)，启动一个秒表计时；当所有灯泡都点亮时，停止秒表计时。这就是振荡器循环256次所需要的时间。假设这个时间为10s，则振荡器的频率是 $2 5 6 \\div 1 0$ ，即 $2 5 . 6 \\mathrm { H z } _ { \\mathrm { \\Omega } }$\n\n随着触发器功能的增加，它的结构也变得更加复杂，下面给出了一个带预置和清零功能的边沿型D触发器。\n\n通常情况下，预置和清零信号输入会覆盖时钟和数据端输入，且两个输入都为0，当预置信号为1时，Q变为1， $\\overline { { \\mathsf { Q } } }$ 变为 $\\scriptstyle 0 _ { \\circ }$ 当清零信号为1，Q变为0， $\\overline { { \\mathbf { Q } } }$ 变为1（同 R-S触发器中的S和R输入端一样，预置和清零信号不能同时为1)。除此之外，该触发器工作原理是和普通边沿D触发器是一样的。\n\n编码隐匿在计算机软硬件背后的语言\n\n184","previous_page":183,"next_page":185}