ZModem通讯程序开发的例子 我们常说的Modem，其实是Modulator（调制器）与Demodulator（解调器）的简称，中文称为调制解调器。也有人跟据Modem的谐音，亲昵地称之为“猫”。我们知道，计算机内的信息是由“0”和“1”组成数字信号，而在电话线上传递的却只能是模拟电信号。于是，当两台计算机要通过电话线进行数据传输时，就需要一个设备负责数模的转换。这个数模转换器就是我们这里要讨论的Modem。计算机在发送数据时，先由Modem把数字信号转换为相应的模拟信号，这个过程称为“调制”。经过调制的信号通过电话载波传送到另一台计算机之前，也要经由接收方的Modem负责把模拟信号还原为计算机能识别的数字信号，这个过程我们称“解调”。正是通过这样一个“调制”与“解调”的数模转换过程，从而实现了两台计算机之间的远程通讯。-dial communications program example, we often said that the modem is actually Modulator (modulator) and Demodulator (demodulator) referred to the Chinese as a modem. It was also According Modem transliterations disputed call "cat." We know that the computer information is from "0" and "1" digital signal components, and the transfer of telephone lines has only analog signals. So, when two computers through telephone lines for data transmission, the need for a digital-analog equipment conversion. The Digital is here to discuss the modem. The computer sent the data, the first Modem signal conversion figures for the corresponding analog signals, the process is known as "modulation." After modulated carrier signal transmitted by telephone to another compu 下载
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ARM开发详解-教程1 ARM（Advanced RISC Machines），既可以认为是一个公司的名字，也可以认为是对一类微处理器的通称，还可以认为是一种技术的名字。 1991年ARM公司成立于英国剑桥，主要出售芯片设计技术的授权。目前，采用ARM技术知识产权（IP）核的微处理器，即我们通常所说的ARM微处理器，已遍及工业控制、消费类电子产品、通信系统、网络系统、无线系统等各类产品市场，基于ARM技术的微处理器应用约占据了32位RISC微处理器75％以上的市场份额，ARM技术正在逐步渗入到我们生活的各个方面。 ARM公司是专门从事基于RISC技术芯片设计开发的公司，作为知识产权供应商，本身不直接从事芯片生产，靠转让设计许可由合作公司生产各具特色的芯片，世界各大半导体生产商从ARM公司购买其设计的ARM微处理器核，根据各自不同的应用领域，加入适当的外围电路，从而形成自己的ARM微处理器芯片进入市场。目前，全世界有几十家大的半导体公司都使用ARM公司的授权，因此既使得ARM技术获得更多的第三方工具、制造、软件的支持，又使整个系统成本降低，使产品更容易进入市场被消费者所接受，更具有竞争力。-ARM Elaborates on-one tutorial ARM (Advanced RISC Machines) It could be that a companys name and can be considered to be a type known as the microprocessor, also can be considered a technical name. 1991 ARM company was established in Cambridge, UK, the sale of chip design technology mandate. At present, the technology used ARM Intellectual Property (IP) Core microprocessors, that is, we usually refer to as the ARM microprocessor, which cover the industrial control, and consumer electronic products, communications systems, network systems, wireless systems and other products market, Based on the ARM microprocessor technology application was about a 32-bit RISC microprocessor 75% above the share of the market, ARM technology is gradually infiltrated into our lives in various areas. ARM 下载
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