CDMA for cellular systems can be described as follows.As with FDMA，each cell is allocated a frequency（ ），which is split into two parts,half for reverse（mobile unit to base station）and half for（ ）（base station to mobile unit）.For full-duplex（本题）.a mobile u
题目
B.transmission
C.compromise
D.communication
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参考答案和解析
更多“CDMA for cellular systems can be described as follows.As with FDMA，each cell is allocated a frequency（ ），which is split into two parts,half for reverse（mobile unit to base station）and half for（ ）（bas”相关问题
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第1题：
When you compare the differences between half-duplex and full-duplex Ethernet, which of the following characteristics are exclusive to half-duplex? (Select two answer choices)
A．Half-duplex Ethernet operates in a shared collision domain.
B．Half-duplex Ethernet operates in an exclusive broadcast domain.
C．Half-duplex Ethernet has efficient throughput.
D．Half-duplex Ethernet has lower effective throughput.
E．Half-duplex Ethernet operates in an exclusive collision domain.
正确答案：AD
解析：Explanation:
A single device could not be sending a frame. and receiving a frame. at the same time because it would mean that a collision was occurring. So, devices simply chose not to send a frame. while receiving a frame. That logic is called half-duplex logic.
Ethernet switches allow multiple frames to be sent over different ports at the same time. Additionally, if only one device is connected to a switch port, there is never a possibility that a collision could occur. So, LAN switches with only one device cabled to each port of the switch allow the use of full-duplex operation. Full duplex means that an Ethernet card can send and receive concurrently.
Incorrect Answers:
B. Full duplex effectively doubles the throughput of half-duplex operation, because data can be both sent and received at the full 10/100 speed.
C, E. In half duplex operation, the network is shared between all devices in the collision domain.
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第2题：
Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two answer choices.)
A．Full-duplex Ethernet uses CSMA/CD to prevent collisions.
B．Half-duplex Ethernet uses a loopback circuit to detect collisions.
C．A full-duplex Ethernet card allows 20Mbps for data transmission.
D．Full-duplex Ethernet makes use of two pairs of wires for data.
E．An Ethernet hub can operate both half and full duplex simultaneously.
正确答案：BD
解析：Explanation:
Half-duplex Ethernet send and receives on the same line, so a loopback needs to be set to detect collisions. Alternatively, full-duple Ethernet doesn't have to because it uses two pairs of wire, one to send and the other to receive. Collisions are not possible on full duplex Ethernet networks.
Incorrect Answers:
A. Full duplex uses both pairs of wires, so transmissions are sent on the first pair, and data that is received come in on the other pair. This prevents collisions.
C. Full duplex allows for data to be sent and received at the same time. It will not double the amount of bandwidth at any given time. The speed of the Ethernet link will remain at 10/100.
E. Hubs are shared devices and can only support one mode, unlike switches.
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第3题：
______ is a contiguous, numbered set of variables of a given base type, which can be used and passed to functions as a unit.
A．Record
B．Array
C．File
D．Parameter
正确答案：B
解析：译文的含义是：()是给定了基类型的连续编号的变量集合，它能够作为参数传递给函数使用。A、B、C、D各选项的意思分别是：记录、数组、文件、参数。所以，根据题目的描述，应该选择数组。 -
第4题：
A server has a single, half height, PCI－X 3.3v slot available. Which of the following cards can fit in this slot? ()A. Half Height, Universally Keyed PCI card
B. Full Height, 3.3v PCI-X card
C. Half Height, x16 PCI Express Card
D. Half Height, 3.3v PCI card
E. Half Height, Universally Keyed PCI-X card
F. Full Height, Universally Keyed PCI card
G. Half Height, x8 PCI Express Card
参考答案：A, D, E
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第5题：
根据下面资料，回答题
I′ve often wondered how exactly sleep, or lack of it, can have such an awful effect on our bodies and, guess what, how much we sleep switches good genes on and bad genes off.
In the first half of 2013, the Sleep Research Centre at the University of Surrey found a direct link between hours spent sleeping and genes. Every cell in our bodies carries genetic instructions in our DNA that act as a kind of operating handbook. However, each cell only "reads" the part of this handbook it needs at any given moment.
Can sleep affect how a gene reads instructions It′s a question asked by Professor Derk-Jan Dijk at the University of Surrey. He set up an experiment and asked his volunteers to spend a week sleeping around seven and a half hours to eight hours a night and the next sleeping six and a half to seven hours.
Blood samples were taken each week to compare which genes in blood cells were being used during the long and short nights. The results were rather surprising. Several hundred genes changed in the amount they were being used, including some that are linked to heart disease, cancer, and Type 2 diabetes. Genes to do with cell repair and replacement were used much less.
Sleep restriction (six and a half to seven hours a night) changed 380 genes. Of these,220 genes were down regulated (their power was reduced), while 160 were up regulated (their power was increased). Those affected included body-clock genes which are linked to diabetes. One of the most downgraded genes is that which has a role in controlling insulin and is linked to diabetes and insomnia. The most upgraded gene is linked to heart disease.
So changing sleep by tiny amounts can upgrade or downgrade genes that can influence our health and the diseases we suffer from when we sleep too little.
The important message is that getting close to eight hours of sleep a night can make a dramatic difference to our health in just a few days through the way it looks after our genes.
What can we learn about Professor Derk-Jan Dijk′ s experiment 查看材料A.The experiment was carried out to find the answer to how genes affect sleep.
B.The experiment took a period of more than two weeks to reach a conclusion.
C.His volunteers were divided into two groups with two different sleeping patterns.
D.Blood samples of the volunteers were checked afterwards to decide how many genes changed in sleeping.答案：B解析：推断题。定位于第三段和第四段。根据第三段的第一句话“Can sleep affect how a gene reads instructions ”可知Derk-Jan Dijk教授的实验是为了发现睡眠对人体基因变化的影响．而不是基因影响睡眠，故A项不正确。根据第三段的最后一句话“He set up an experiment and asked his volunteers to spend a week sleeping around seven and a half hours to eight hours a night and the next sleeping six and a half to seven hours．”可知，他并没有将志愿者进行分组，而是要求他们第一周每晚睡七个半到八个小时，第二周将睡眠时间调整为六个半到七个小时，故C项不正确。再结合第四段的前两句话，他将志愿者这两周的血液样本进行比对，观察基因运作情况的不同．实验结果令人大吃一惊。由此可推断出，这个实验进行了两周多才得出结论，故B项正确，D项不正确，采集血液样品是为了比较在不同睡眠时长下所用到的基因的不同，而不是多少基因被改变。 -
第6题：
A server has a single， half height， PCI-X 3.3v slot available. Which of the following cards can fit in 1 this slot？（）
- A、 Half Height， Universally Keyed PCI card
- B、 Full Height， 3.3v PCI-X card
- C、 Half Height， x16 PCI Express Card
- D、 Half Height， 3.3v PCI card
- E、 Half Height， Universally Keyed PCI-X card
- F、 Full Height， Universally Keyed PCI card
- G、 Half Height， x8 PCI Express Card
正确答案:A,D,E -
第7题：
Which logical channel must be dimensioned for each cell when considering the call set-up frequency? （）
- A、SACCH
- B、SDCCH
- C、FCCH
- D、SCH
- E、BCCH
正确答案:B -
第8题：
半纵列式中间站 intermediate station with half longitudinal arrangement
正确答案: 上、下行到发线有效长部分错开布置的中间站。 -
第9题：
A customer plans to consolidate multiple business unit applications on a single Power Systems server. The maximum number of cores which can be used by each business unit must be limited by creating shared processor pools. What is the minimum PowerVM Edition which provides this feature?（）
- A、Basic
- B、Express
- C、Standard
- D、Enterprise
正确答案:C -
第10题：
单选题For a continuous operation diesel engine, a duplex filter unit would be the best arrangement because （）.Achanging filter elements would not interrupt engine operation
Bfiltering occurs twice in each pass of oil through the system
Cclogging will not occur
Ddropping pressure is half of that through a single filter unit
正确答案： A解析： 暂无解析 -
第11题：
多选题When troubleshooting duplex mismatches， which two are errors that are typically seen on the half duplex end？（）Aexcessive collisions
BFCS errors
Crunts
Dlate collisions
正确答案： B,C解析： 暂无解析 -
第12题：
多选题When troubleshooting duplex mismatches， which two are errors that are typically seen on the half duplexend？（）Aexcessive collisions
BFCS errors
Crunts
Dlate collisions
正确答案： D,A解析： 暂无解析 -
第13题：
We’ll leave our school in________.A.two year and a half
B.two years and a half
C.two and half a years
D.two and half a year
参考答案：B
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第14题：
For a continuous operation diesel engine, a duplex filter unit would be the best arrangement because
A.changing filter elements would not interrupt engine operation
B.filtering occurs twice in each pass of oil through the system
C.clogging will not occur
D.dropping pressure is half of that through a single filter unit
正确答案：A
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第15题：
Bluetooth is a universal radio interface in the(71)frequency hand that enables portable electronic devices to connect and communicate wirelessly via short-range, ad hoc networks. Each unit can simultaneously communicate with up to(72)other units per piconet. Moreover, each unit can simultaneously(73)to several piconets. Eliminates the need for wires, cables and connectors for and between cordless or mobile phones, modems, headsets, PDAs, Computers, printers, projectors, local area networks, and so on, and paves the way for new and completely different devices and applications. Technology Characteristics(74)symbol rate exploits maximum available(75)bandwidth。
A．1.95GHz
B．2.45GHz
C．4.45GHz
D．11.45GHz
正确答案：B
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第16题：
CDMA for cellular system can be described as follows. As with FDMA, each cell is allocated a frequency （71） , when is split into two parts, half for reverse (mobile unit to base station) and half for （72） (base station to mobile unit). For full-duplex （73） , a mobile unit both reverse and forward channels. Transmission is in the form. of direct-sequence spread （74） , which used a chipping code to increase the data rate of the transmission, resulting is an increased signal bandwidth. Multiple access is provided by assigning （75） chipping codes to multiple users, so that the receiver can recover the transmission of an individual unit from multiple transmissions.
A.ware
B.signal
C.bandwidth
D.domain
正确答案：C
用于蜂窝系统的CDMA技术可以描述如下。就像FDMA一样，每一个小区被分配了一个频带，该频带划分为两半，一半用于反向信道（从移动终端到基站），一半用于正向信道（从基站到移动终端）。在全双工通信中，移动终端使用了反向和正向两个信道。传输以直接序列扩频方式进行，用一个码片来增加传输的数据速率，同时也产生了额外的信号带宽。通过把正交的各个码片指定给不同的用户就可以实现多路访问，这样接收者就能够从多个传输中提取并恢复需要的传输单元。 -
第17题：
CDMA for cellular systems can be described as follows.As with FDMA，each cell is allocated a frequency（ ），which is split into two parts,half for reverse（mobile unit to base station）and half for（ ）（base station to mobile unit）.For full-duplex（ ）.a mobile unit uses both reverse and forwardchannels.Transmission is in the form of direct-sequence spread（本题）,which uses a chipping code to increase the data rate of the transmission,resulting inan increased signal bandwidth.Multiple access is provided by assigning（ ）chipping codes to multiple users,so that the receiver can recover the transmission of an individual unit from multiple transmissions.A.structure
B.spectrum
C.stream
D.strategy答案：B解析：见下题 -
第18题：
When one connection to a host fails in a full mesh network， which of the following is true？（）
- A、All hosts can communicate.
- B、No hosts can communicate.
- C、Half of the hosts will lose communication.
- D、Only the two hosts between the failed connection will lose communication.
正确答案:A -
第19题：
What is the point of using a combiner? （）
- A、Up to four sites can share one PCM link.
- B、Several TRXs can share one antenna system.
- C、The mobile can listen to two base stations at the same time.
- D、Only one base station is needed per site.
- E、Sending and transmitting can be performed from the same antenna.
正确答案:B -
第20题：
Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet?（）
- A、Full-duplex Ethernet uses CSMA/CD to prevent collisions.
- B、Half-duplex Ethernet uses a loopback circuit to detect collisions.
- C、A full-duplex Ethernet card allows 20Mbps for data transmission.
- D、Full-duplex Ethernet makes use of two pairs of wires for data.
- E、An Ethernet hub can operate both half and full duplex simultaneously.
正确答案:B,D -
第21题：
单选题In Ethernet networks, duplex mismatches will lower performance. Which error statistics can be seen if a duplex mismatch is present?（）Acollisions on the full-duplex side; runts on the half-duplex side
Bcollisions on the full-duplex side; collisions on the half-duplex side
Ccollisions on the half-duplex side; framing errors on the full-duplex side
Dcollisions on the half-duplex side; giants on the full-duplex side
正确答案： A解析： 暂无解析 -
第22题：
单选题A mobile earth station in the maritime mobile-satellite service,which is located on board ship,is called（）.Aan LES
Ban SES
Ca ship station
Da Land Mobile Station
正确答案： D解析： 暂无解析 -
第23题：
单选题The fuel oil system for a diesel engine can be considered in two parts--the fuel supply and the （） systems.Afuel treatment
Bfuel combustion
Cfuel injection
Dfuel separating
正确答案： D解析： 暂无解析 -
第24题：
单选题Which statement is true about full-duplex Ethernet in comparison to half-duplex Ethernet?（）AFull-duplex Ethernet consists of a shared cable segment. Half-duplex Ethernet provides a point-to-point link.
BFull-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex Ethernet uses a jam signal.
CFull-duplex Ethernet can provide higher throughput than can half-duplex Ethernet of the same bandwidth.
DFull-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receive.
正确答案： B解析： 暂无解析