{"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":164,"pdf_page":180,"physical_index":180,"physical_index_base":0,"printed_page_status":"recognized","page_sha256":"580f88200bb9d27460f8420332f0f53f210506f54b93f4fa132fa3bc03883a09"},"chapter":"编码隐匿在计算机软硬件背后的语言","content":"一个循环所占用的时间就是该振荡器的周期（period)。假设我们使用的振荡器的周期恰好是0.05s，任取一个时间点，将其设置为起始状态点，我们把它标注为零点，就可以在水平轴上标出相应的时间。\n\n周期的倒数就是振荡器的频率(frequency)。在这个例子中振荡器的周期是0.05s，那么其频率就是1÷0.05s，即振荡器每秒钟产生20次循环，而相应的输出每秒钟也变化20次。\n\n每秒钟的循环次数与每小时穿越的英里数、每平方英尺的重量、每份食物的卡路里数等概念一样都是很容易理解的，但这种描述方法已不常用。为了纪念发送和接收无线电波的第一人—亨利希·鲁道夫·赫兹（1857-1894)，后人使用“赫兹”这个词来表示这一概念。这种用法起源于20世纪20年代的德国，几十年之后逐渐被其他国家所广泛采纳。\n\n这样，上述振荡器的频率就是20赫兹，记做20Hz。\n\n目前为止，我们还只是在猜测一个振荡器的速度。在本章后面我们将构建一种可以测量振荡器速度的元件。\n\n在此之前，让我们先来看看采用特殊方式连接的一对或非门。或非门的特点是只有在两个输入端都没有电压时，输出端才产生电压。\n\n编码—隐匿在计算机软硬件背后的语言\n\n164","previous_page":163,"next_page":165}