[单选题]Among the Morse code of DVOR， how much time interval between the dot and mark in the same code?（ ）
A. 100~280ms　
B. 200~380ms　
C. 300~480ms　
D. 400~580ms

[单选题]Among the Morse code of DVOR， how much time interval between the dot and mark in the same code?（ ）
A. 100~280ms　
B. 200~380ms　
C. 300~480ms　
D. 400~580ms

[单选题]Normally， the ident code of DVOR consist of（ ）。
A. dot　
B. mark　
C. letter　
D. pulse

[简答题]My problem is that I don't have much time to do the work.

[单选题]DVOR监控天线背对DVOR天线方向应架设()支避雷针。(3553)
A.1
B.2
C.3

[判断题]在边带天线为48根的DVOR设备DVOR相邻序号的边带天线所馈以的正弦平方波和余弦平方波之间的起始间隔为1/1440秒。(2957)
A.正确
B.错误

[判断题]在边带天线为48根的DVOR设备中DVOR的1号边带天线辐射上边带信号的同时,25号边带天线也在辐射下边带信号。(2956)
A.正确
B.错误

[单选题]DVOR设备由（ ）组成。
A.载波发射机、边带发射机、监控系统、天线系统、电源
B.载波发射机、监控系统、天线系统、电源
C.载波发射机、边带发射机、监控器、天线系统、电源
D.载波发射机、边带发射机、监控器、天线系统

[单选题] How much does a user pay if he has broadband technology installed?
A.It depends on the length of time.
B.It depends on the times of dial-up.
C. He pays at a fixed monthly rate.
D.He pays a lot of money.

[填空题]Passage 15

How much do you know about manners（礼仪）? Different countries have different manners. In some Asian countries, it is good manners to take off your 21before you go into a house. But in European (欧洲)countries, even if they sometimes become very dirty, this is not done. If you are a 22in a Chinese house, when you have a meal, you usually do not finish the food. You often leave a little to show that you have had enough. But in England, a visitor always finishes food to show that he has 23 it. We must know the customs of other 24,so that they will not think 25bad-mannered. People all over the world agree that a well-mannered person should be kind and helpful to others. If you remember this, at least you will not go very far wrong. Everybody likes a person with good manners, but no one likes a person with bad manners. Keep your manners.

A. countries   B. foreigner   C. enjoyed    D. us   E. shoes

[单选题]DVOR音频复合信号不包括（ ）。
A. 30HzAM基准相位信号　
B. 键控的1020Hz信号　
C. 载波信号　
D. 被30Hz可变相位信号调频的9969Hz副载波

[单选题]DVOR射频的频率范围是（ ）。
A. 108MHz～117.95MHz　
B. 107.95MHz～118MHz　
C. 108MHz～111.95MHz　
D. 108.1MHz～111.95MHz

[单选题]DVOR是 Doppler （ ） omnidirectional radio rang的缩写。
A.VHF
B.VFN
C.VCD
D.Very

[单选题]DVOR设备的信号流程为（ ）。
A.发射机-天线开关网络-天线系统
B.发射机-天线系统
C.发射机-开关网络-天线系统-监控器
D.发射机-天线系统-监控器

[判断题]DVOR辐射必须为水平极化波。
A.正确
B.错误

[单选题]DVOR射频的波道间隔是（ ）。
A. 0.05MHz　
B. 0.15MHz　
C. 0.5MHz　
D. 5MHz