2018年中级通信工程师传输与接入每日一练（7-31）

责编：刘政 2018-07-31

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目前传输与接入专业已经分为两个不同的方向：无线与有线，由于新版本刚出，所以目前每日一练不区分无线与有线，后期会有不同版本的每日一练公布。

1、通信卫星中的双变频转发器先把接收到的上行信号变为（）信号，经放大限幅以后再变为下行信号。
处理转发器则要对信号进行（）处理，然后经过重新调制、上变频、功率放大后发向地面站。

A．基带
B．中频
C．射频
D．数字

A．放大
B．压缩
C．交换
D．解调

2、下列调制方式中，（）是ITU-T关于ADSL标准建议采用的。

A．2B1Q
B．DMT
C．TC-PAM
D．BPSK

3、会议电视业务向用户提供以视觉为主、多媒体的视像通信，其接入方式基于（）接入组网。

A．宽带
B．窄带
C．移动
D．无线

4、第三代移动通信（3G）与第二代移动通信（2G）相比，提供的新业务能力是（）。

A．三方通话等语音增值服务
B．话费查询等数据增值服务
C．短信息业务
D．高于300kbps的数据下载业务

5、电信运营商提供的虚拟网业务可以实现（）的功能，且可帮助用户大大节省投资费用。

A．用户小交换机
B．短信平台
C．宽带接入
D．视频监控

6、CPU通过总线与内存和输入/输出设备连接，下列说法错误的是（）。

A．总线是连接CPU、内存、I/O设备等部件的一组公共信号线

B．总线分数据总线、地址总线和控制总线，程序指令和数据都存于内存，其中数据通过数据总线调入调出CPU，而程序指令通过控制总线调入CPU执行

C．DMA技术使外围设备与CPU并行工作，直接将数据在外设和内存之间交换
D．内存的工作速度相对于CPU的运算速度要低很多

7、为兼顾稳定性、可靠性和经济性，在通信网中经常采用（）的网络拓扑结构。

A．网状图

B．星型网

C．环型网

D．复合型网

8、With the explosive popularity of mobile devices, we have witnessed a steady increase in demand for mobile date service. In addition mobile users also expect to connect to the Internet for communicate and access to services through the best suitable connection, anywhere and at anytime. Although the seamless roaming capability is well supported in conventional. Cellular communication networks, roaming and interworking technologies are still immature in heterogenous wireless networks. Seamless roaming over heterogenous wireless networks will be an ongoing and improved process, due to the requirements from both end users and network administrators. From the wireless access networks belonging to different administrative domains, mobile users cannot always identify at every instance which network is the best one to access for their service. It is highly demanded to establish a network architecture which can facilitate mobile terminals to access the appropriate network in a cost-effective way. If a mobile user wants to move from one network to another with continuous service, the terminals have to cope with network change to maintain service seamlessly. Quality of service is a major issue that the end users should be provided with the satisfying service, while the network workload and cost should not too much increased. In addition, since end users are provided with numerous service ranging from Voice-over-IP to Video-on-Demand services, it is expected that users can experience the same quality for all the different service. Therefore, the network architecture need to be designed in such a way that the quality mechanism is incorporated so that users are served according to their individual QoS requirements.

Based on the paragraph above, at present, seamless roaming over heterogenous wireless network is （） in conventional cellular communication networks, Because of （）, mobile users cannot always identify at every instance which network is the best one to access for their services. To satisfy the users QoS requirements, the network architecture design should include （）.

A．better than

B．maturer than

C．as good as

D．not as good as

A．the different network administrative domains

B．the same network administrative domains and mobile users

C．mobile users

D．the same network administrative domains

A．Voice -over -IP

B．the quality mechanism

C．workload

D．Video-on-Demand