第一章 单元测试

1、判断题：
The mobile telephone network in New York could only support small number of subscribers mainly because the power of the base station is too low. （ ）
选项：
A:对
B:错
答案: 【错】

2、判断题：
The first generation WLAN devices had to use low power density scheme because high power devices are very expensive. （ ）
选项：
A:错
B:对
答案: 【错】

3、单选题：
__ is not the reason that why the 1st generation WLAN is not widely used. （ ）
选项：
A:Short coverage.
B:Lack of standardization.
C:Lack of mobility.
D:Low data rate.
答案: 【Lack of mobility.】

4、多选题：
__ and __ are two main disadvantages for high altitude orbits satellite communications. （ ）
选项：
A:High path loss
B:big propagation delay
C:multipath interference.
D:small coverage.
答案: 【High path loss;
big propagation delay】

5、多选题：
The first wireless communication networks in the Pre-industrial age transmitted information by using some simple signals, such like __ signals, __ signal, signal ___, or beating drums. （ ）
选项：
A:laser
B:fire
C:flares
D:smoke
答案: 【fire;
flares;
smoke】

第二章 单元测试

1、多选题：
What can cause power variation in the received signal over the distance? （ ）
选项：
A:constant signal source power
B:path loss
C:shadowing effects
D:free-space propagation
答案: 【path loss;
shadowing effects】

2、单选题：
Which frequency band is used for television communications and radio navigation systems? （ ）
选项：
A:30 MHz -300 MHz
B:3 MHz -30 MHz
C:300 MHz -3 GHz
D:3 kHz -30 kHz
答案: 【3 MHz -30 MHz】

3、判断题：
Path loss and Shadowing are generally referred as large scale propagation effects. （ ）
选项：
A:对
B:错
答案: 【对】

4、判断题：
Fresnel knife edge diffraction model is commonly used diffraction model. （ ）
选项：
A:对
B:错
答案: 【对】

5、判断题：
Shadowing is caused by the amplification of the power radiated by the transmitter and the reflective effects of the propagation channel. （ ）
选项：
A:对
B:错
答案: 【错】