下载APP
举一反三
【单选题】Online services are managed by a host system that maintains a base of information available to satellite users. Users of so-called "dumb" terminals (i. e., those without processing capability)simply a...
A.
Online services are managed by a host system that maintains a base of information available to satellite users. Users of so-called "dumb" terminals (i. e., those without processing capability)simply access the information base via programs stored on the system. Personal computer (PC) users typically access the host through a modem (调制解调器). A PC software program serves as an intece (接口)between the server and a PC, allowing the user to operate through the online system and select different databases using a keyboard or a mouse.
B.
National and regional online systems usually have local telephone numbers that PC modems can call to access either a local information base or an indirect long-distance connection, thus reducing long-distance telephone fees. Some online systems allow users ’to copy large volumes of information onto a local memory storage device, which also reduces the time the user is connected to the online system.
C.
Besides offering a great number of different information based, ranging from full-text journal li- braries to reports of missing children, online services allow users to, for example, reserve airline tick- ets, buy stocks, purchase goods, and communicate with other users. In exchange for the service, users usually pay a monthly membership fee. They may also pay to connect to various databases on the service or to download information.
【单选题】ITU V90调制解调器(MODEM)______。
A.
下载速率是56kb/s，上传速率是33.6kb/s
B.
上下行速率都是56kb/s
C.
与标准X.25公用数据网连接，以56kb/s的速率交换数据
D.
时刻与ISP连接，只要开机，永远在线
【单选题】调制解调器(Modern)的作用是( )。
A.
将数字脉冲信号转换成模拟信号
B.
将模拟信号转换成数字脉冲信号
C.
将数字脉冲信号与模拟信号互相转换
D.
为了上网与打电话两不误
【单选题】调制解调器(Modem)的功能是。
A.
将数字信号转换成模拟信号
B.
将模拟信号转换成数字信号
C.
兼有A和B的功能
D.
使用不同频率的载波将信号变换到不同的频率范围
相关题目：
【单选题】Online services are managed by a host system that maintains a base of information available to satellite users. Users of so-called "dumb" terminals (i. e., those without processing capability)simply a...
A.
Online services are managed by a host system that maintains a base of information available to satellite users. Users of so-called "dumb" terminals (i. e., those without processing capability)simply access the information base via programs stored on the system. Personal computer (PC) users typically access the host through a modem (调制解调器). A PC software program serves as an intece (接口)between the server and a PC, allowing the user to operate through the online system and select different databases using a keyboard or a mouse.
B.
National and regional online systems usually have local telephone numbers that PC modems can call to access either a local information base or an indirect long-distance connection, thus reducing long-distance telephone fees. Some online systems allow users ’to copy large volumes of information onto a local memory storage device, which also reduces the time the user is connected to the online system.
C.
Besides offering a great number of different information based, ranging from full-text journal li- braries to reports of missing children, online services allow users to, for example, reserve airline tick- ets, buy stocks, purchase goods, and communicate with other users. In exchange for the service, users usually pay a monthly membership fee. They may also pay to connect to various databases on the service or to download information.
【单选题】● 调制解调器(MODEM)的主要功能是 （5） 。
A.
模拟信号的放大
B.
数字信号的整形
C.
模拟信号与数字信号的转换
D.
数字信号的编码
【单选题】通信系统按调制方式分为（）
A.
基带传输和频带传输
B.
基带传输和宽带传输
C.
宽带传输和频带传输
D.
模拟信号和数字信号
【多选题】无线通信系统的接收机由（）组成。
A.
天线
B.
滤波器
C.
放大器
D.
A/D转换器
【单选题】ITU V90调制解调器(MODEM)______。
A.
下载速率是56kb/s，上传速率是33.6kb/s
B.
上下行速率都是56kb/s
C.
与标准X.25公用数据网连接，以56kb/s的速率交换数据
D.
时刻与ISP连接，只要开机，永远在线
【单选题】船舶内部的通信系统,一般指的是__。I.电话 II.传令钟 III.广播 IV.警报系统
A.
Ⅰ+Ⅱ+Ⅲ
B.
Ⅰ+Ⅱ+Ⅳ
C.
Ⅱ+Ⅲ+Ⅳ
D.
Ⅰ+Ⅱ+Ⅲ+Ⅳ
【单选题】1G即第一代移动通信系统，主要的业务为（）
A.
数据
B.
语音
C.
短信
D.
彩信
【单选题】第一代蜂窝移动通信系统AMPS的多址方式是（）。
A.
TDMA
B.
CDMA
C.
SDMA
D.
FDMA
【单选题】当通过电话线连接到ISP时，因为电话线路输出信号为哪种信号，计算技术输出信号只能通过调制解调器同电话网连接
A.
数字
B.
模拟
C.
音频
D.
模拟数字
【单选题】调制解调器(Modern)的作用是( )。
A.
将数字脉冲信号转换成模拟信号
B.
将模拟信号转换成数字脉冲信号
C.
将数字脉冲信号与模拟信号互相转换
D.
为了上网与打电话两不误
【单选题】相干光通信系统又成为（ ）
A.
外调制光纤通信系统
B.
间接调制光纤通信系统
C.
外差光纤通信系统
D.
内调制光纤通信系统
【单选题】调制解调器(modem)的主要功能是
A.
模拟信号的放大
B.
数字信号的编码
C.
模拟信号与数字信号的转换
D.
数字信号的放大
【单选题】调制解调器(Modem)的功能是。
A.
将数字信号转换成模拟信号
B.
将模拟信号转换成数字信号
C.
兼有A和B的功能
D.
使用不同频率的载波将信号变换到不同的频率范围
【单选题】调制解调器的英文名是( )。
A.
Modem
B.
Bridge
C.
Router
D.
Gateway