{"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":87,"pdf_page":103,"physical_index":103,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"8be391f707bac97cd9ab6014668f723b91f89caeff0628e2f01ac4270397da0b"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"计算机就会使用如下表来解码。\n\n逆向扫描时右边數字的編码\n\n$$\n0 1 0 0 1 1 1 = 0\n$$\n\n$$\n0 1 1 1 0 0 1 = 5\n$$\n\n$$\n0 1 1 0 0 1 1 = 1\n$$\n\n$$\n0 0 0 0 1 0 1 = 6 \n$$\n\n$$\n0 0 1 1 0 1 1 = 2\n$$\n\n$$\n0 0 1 0 0 0 1 = 7\n$$\n\n$$\n0 1 0 0 0 0 1 = 3\n$$\n\n$$\n0 0 0 1 0 0 1 = 8 \n$$\n\n$$\n0 0 1 1 1 0 1 = 4\n$$\n\n$$\n0 0 1 0 1 1 1 = 9\n$$\n\n以下是对左边数字的解码表。\n\n逆向扫描时左边數字的編码\n\n$$\n1 0 1 1 0 0 0 = 0 \n$$\n\n$$\n1 0 0 0 1 1 0 = 5 \n$$\n\n$$\n1 0 0 1 1 0 0 = 1 \n$$\n\n$$\n1 1 1 1 0 1 0 = 6 \n$$\n\n$$\n1 1 0 0 1 0 0 = 2 \\ \\AA\n$$\n\n$$\n1 1 0 1 1 1 0 = 7 \\ \\qquad \n$$\n\n$$\n1 0 1 1 1 1 0 = 3\n$$\n\n$$\n1 1 1 0 1 1 0 = 8 \n$$\n\n$$\n1 1 0 0 0 1 0 = 4\n$$\n\n$$\n1 1 0 1 0 0 0 = 9\n$$\n\n所有这些7位编码都与由左向右扫描时得到的UPC完全不同。这里不会有模棱两可的现象存在。\n\n在这本书中我们是从莫尔斯码开始接触编码的，莫尔斯码是由点和划组成的，且点和划之间由一定的时间间隔分开。尽管莫尔斯码乍看上去并不像是由0和1组成的，然而它们却是等价的。\n\n回顾一下莫尔斯码的编码规则：划的长度等于点长度的三倍；单个字母内，点或划之间以长度与点相等的空格来分开；单词内的各个字母之间用长度等于划的空格分隔；各单词之间由长度等于两倍的划的空格分开。\n\n让我们将分析简化一些，假设一个划的长度是点长度的两倍，而不是三倍。这就意味着一个点就是一个值为1的比特位，一个划是两个值为1的比特位，空格则是值为0的比特位。\n\n下面是第2章中莫尔斯码的基本表。\n\n9 二进制数\n\n87","previous_page":86,"next_page":88}