用频谱仪测量天线输入的下行功率强度时需要填写“天线场强测试表。从人体安全辐射范围要求

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问题:

用频谱仪测量天线输入的下行功率强度时需要填写“天线场强测试表。从人体安全辐射范围要求考虑,要求天线的发射功率不大于()dBm/载波(天线的发射功率=天线输入的下行功率+天线增益)。电梯井中天线的发射功率不大于()dBm/载波。

A、8

B、10

C、15

D、20

考点:通信工程师TD认证综合试题TD认证综合试题题库
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表达式1+2+"aa"+3的值为

A."12aa3"

B."3aa3"

C."12aa"

D."aa3"

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Visitors to this country are normally admitted for six months, but foreign students can usually stay for one year. They must (52) an educational institution, and they are required to study for a (53) of fifteen hours a week on a daytime course. Prospective students have to show that they can afford their studies, and that they have sufficient (54) resources to support themselves (55) in this country.

In order to work here the foreigner needs a work permit, (56) must be applied for by his prospective employer. The problem here is that the Department of Employment has the right to grant or (57) these permits, and there is little that can be done (58) it; it would be extremely unwise for a foreign visitor to work (59) a permit, since anyone doing so is liable to immediate deportation (驱逐出境). There are some people from the European countries, who are often given (60) residence permits of up to five years. Some other people, such as doctors, foreign journalists, authors and others can work without permits, and foreign students are normally allowed to (61) part-time jobs while they are studying here.

58().

A.for 

B.on 

C.about 

D.with

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地理信息系统产品的输出形式有多种,就其载体形式来说,可分为常规地图和数字地图,以下属于后者的是()

A.遥感影像地图

B.屏幕地图

C.电子地图

D.动态地图

E.出版印刷的地形图

题型:多项选择题

分拣作业的环节有()。

A.产生拣货信息

B.行走搬运

C.集中包装

D.拣取

E.分类集中

题型:多项选择题

带传动中,在同样的初拉力作用下,横截面为梯形的三角胶带和横截面为矩形的平胶带承载力相比较,()。

A、三角胶带大;

B、平胶带大;

C、一样大;

D、承载力不均。

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