调制解调器的设计

介绍Ａｍ７９１０为主的移频键控调制解调器的设计．现有的国内通讯系统多数是利用现有的模拟通讯系统（如：电话线，短波无线电台等）来实现数字信号的传输（如计算机通信，传真等），就必须用一种将数字信号转换成模拟信号，或把模拟信号转换成数字信号的装置．这个装置人们通常称它为数字调制调器（ＭＯＤＥＭ）．笔者在设计过程，主要解决了计算机键控调制解调器的设计及计算机ＲＳ—２３２Ｃ，语言通信线路的接口，收发技术等问题．

Design of the Modulator-Demodulator

The design of the modulator-demodulator which has changing frequency and is keyed by a computer is introduced in the paper.Most of the existing domestic communication systems are analog communications systems.Their transmission band frequency has certain restriction.To transmit digital signal with the present existing analog communication system (such as,telephone line,short-wave radio broadcasting station,etc ...),a device which can convert digital signal into analog signal and convert analog signal into digital signal is needed' Such device is called modulator-demodulator. This paper designed one which is keyed by a computer.The paper atso solved the problem of the interface between the computer RS-232C and its language communication wire and of receiving and giving orders.