Spread Spectrum扩展频谱
第1题：
●In the following essay，each blank has four choices．Choose the best answer and write down on the answer sheet．
Spread spectrum simply means that data is sent in (66) pieces over a number of the discrete frequencies available for use at any time in the specified range．Devices using (67) spread spectrum(DSSS)communicate by splitting each (68) of data into several parts and sending them concurrently on different (69) ,DSSS uses a lot of the available (70) ，about 22 megahertz(MHz)．
(66) A．small
B．high
C．low
D．long
(67) A．direct-sequence
B．discrete-sequence
C．duplicate-sequence
D．dedicate-sequence
(68) A．data
B．byte
C．packet
D．bit
(69) A．bits
B．frequencies
C．packets
D．messages
(70) A．rate
B．velocity
C．bandwidth
D．period
第2题：
In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.
Spread spectrum simply means that data is sent in(66)pieces over a number of the discrete frequencies available for use at any time in the specified range. Devices using(67) spread spectrum (DSSS)communicate by splitting each(68)of data into several parts and sending them concurrently on different (69), DSSS uses a lot of the available(70), about 22 megahertz (MHz).
A．small
B．high
C．low
D．long
第3题：
A.直接序列扩频(Direct Sequence Spread Specm，DSSS)
B.跳频扩频(Frequency Hopping Spread spectunu FHSS)
C.跳时(Time Hopping，TH)
D.线性调频(Chirp )
第4题：
扩频通信技术，即扩展频谱通信（Spread Spectrum Communication），它与（）一同被誉为进入信息时代的三大高技术通信传输方式。
第5题：
A.IR
B.DSSS
C.FHSS
D.DSSS and FHSS
E.IR, FHSS, and DSSS
第6题：
关于维纳频谱的叙述，错误的是
A、维纳频谱即Wiener spectrum，(WS)
B、△D(x)的自相关函数的付氏变换为WS
C、用WS分析形成X线照片斑点的原因
D、维纳频谱可以确定不同频率的RMS
E、维纳频谱也称量子检出效率
第7题：
Spread spectrum simply means that data is sent in small pieces Over a number of the(46)frequencies available for use at any time in the specified range. Devices using(47)spread spectrum (DSSS)communicate by(48)each byte of data into several parts and sending them concurrently on different(49). DSSS uses a lot of the available(50), about 22 megahertz (MHz).
A．continuous
B．high
C．low
D．discrete
第8题：
根据下面的文字资料回答 71～75 题 In the following essay．each blank has four choices．Choose the best answer and write down on the answer sheet．
Spread spectrum simply means that data is sent in（ 1 ）pieces over a number of the discrete frequencies available for use at any time in the specified range．Devices using（ 2 ） spread spectrum(DSSS)communicate by splitting each（ 3 ）of data into several parts and sending them concurrently on different（ 4 ），DSSS uses a lot of the available（ 5 ），about 22 megahertz(MHz)．
第71题：文中（ 1 ）处正确的答案是（ ）。
A．small
B．high
C．low
D．long
第9题：
A.DSSS
B.FHSS
C.OFDM
D.CDMA
第10题：
扩频（spread-spectrum）技术是使用ISM频带传输无线数据的基础。