网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
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
B.spectrum
C.stream
D.strategy
参考答案
参考解析
解析：见下题
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（ ）（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” 相关考题
考题
【An overall cellular network contains a number of different elements from the base transceiver station (BTS) itself with its antenna back through a base station controller (BSC), and a mobile switching centre (MSC) to the location registers (HLR and VLR) and the link to the public switched telephone network (PSTN). Of the units within the cellular network, the BTS provides the direct communication with the mobile phones. There may be a small number of base stations then linked to a base station controller. This unit acts as a small centre to route calls to the required base station, and it also makes some decisions about which of the base station is best suited to a particular call. The links between the BTS and the BSC may use either land lines of even microwave links. Often the BTS antenna towers also support a small microwave dish antenna used for the link to the BSC. The BSC is often co-located with a BTS. The BSC interfaces with the mobile switching centre. This makes more widespread choices about the routing of calls and interfaces to the land line based PSTN as well as the HLR and VLR.】 From the paragraph above, in a cellular network, the （98） can provide direct communication with a mobile phone, the （99） acts as a small centre to route calls to the required base station, and it also makes some decisions about which of the base station is best suited to a particular call.（100） can be used to link the BSC with related BTS。A. BSC B. BTS C. MSC D. VLR A. BSC B. BTS C. MSC D. HLR A. Land lines B. Microwave links C. Microwave dish antenna D. Land lines or microwave links
考题
You want to upgrade the Ezonexam LAN so that all ports operate in full duplex mode. Which statement is true about full-duplex Ethernet when comparing to half-duplex Ethernet?A．Full-duplex Ethernet consists of a shared cable segment. Half-duplex provides a point-to-point linkB．Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receiveC．Full-duplex Ethernet can provide higher throughput than can half-duplex Ethernet of the same bandwidthD．Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex Ethernet uses a jam signalE．None of the above
考题
The Ezonexam LAN is upgrading all devices to operate in full duplex. Which statement is true about full-duplex Ethernet in comparison to half-duplex Ethernet?A．Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receiveB．Full-duplex Ethernet consists of a shared cable segment. Half-duplex Ethernet provides a point-to-point linkC．Full-duplex Ethernet can provide higher throughout than can half-duplex Ethernet of the same bandwidthD．Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex ethernet uses a jam signalE．None of the above
考题
The maximum data rate of any single wireless link can be described by the shannons theorem which is related to the（）in hertz，and the（）on the channelA．signal frequency B．bandwidth C．carrier frequency D．noise frequency A．signal B．caeeier C．noise D．data signal
考题
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.
考题
We’ll leave our school in________.
A.two year and a halfB.two years and a halfC.two and half a yearsD.two and half a year
考题
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.
考题
For a continuous operation diesel engine, a duplex filter unit would be the best arrangement becauseA.changing filter elements would not interrupt engine operationB.filtering occurs twice in each pass of oil through the systemC.clogging will not occurD.dropping pressure is half of that through a single filter unit
考题
______ is a contiguous, numbered set of variables of a given base type, which can be used and passed to functions as a unit.A．RecordB．ArrayC．FileD．Parameter
考题
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．1.95GHzB．2.45GHzC．4.45GHzD．11.45GHz
考题
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 cardB. Full Height, 3.3v PCI-X cardC. Half Height, x16 PCI Express CardD. Half Height, 3.3v PCI cardE. Half Height, Universally Keyed PCI-X cardF. Full Height, Universally Keyed PCI cardG. Half Height, x8 PCI Express Card
考题
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.wareB.signalC.bandwidthD.domain
考题
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.
考题
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 cardB、 Full Height， 3.3v PCI-X cardC、 Half Height， x16 PCI Express CardD、 Half Height， 3.3v PCI cardE、 Half Height， Universally Keyed PCI-X cardF、 Full Height， Universally Keyed PCI cardG、 Half Height， x8 PCI Express Card
考题
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.
考题
Which logical channel must be dimensioned for each cell when considering the call set-up frequency? （）A、SACCHB、SDCCHC、FCCHD、SCHE、BCCH
考题
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.
考题
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.
考题
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、BasicB、ExpressC、StandardD、Enterprise
考题
单选题In Ethernet networks, duplex mismatches will lower performance. Which error statistics can be seen if a duplex mismatch is present?（）A
collisions on the full-duplex side; runts on the half-duplex sideB
collisions on the full-duplex side; collisions on the half-duplex sideC
collisions on the half-duplex side; framing errors on the full-duplex sideD
collisions on the half-duplex side; giants on the full-duplex side
考题
单选题For a continuous operation diesel engine, a duplex filter unit would be the best arrangement because （）.A
changing filter elements would not interrupt engine operationB
filtering occurs twice in each pass of oil through the systemC
clogging will not occurD
dropping pressure is half of that through a single filter unit
考题
单选题A mobile earth station in the maritime mobile-satellite service,which is located on board ship,is called（）.A
an LESB
an SESC
a ship stationD
a Land Mobile Station
考题
多选题When troubleshooting duplex mismatches， which two are errors that are typically seen on the half duplex end？（）Aexcessive collisionsBFCS errorsCruntsDlate collisions
考题
单选题The fuel oil system for a diesel engine can be considered in two parts--the fuel supply and the （） systems.A
fuel treatmentB
fuel combustionC
fuel injectionD
fuel separating
考题
多选题When troubleshooting duplex mismatches， which two are errors that are typically seen on the half duplexend？（）Aexcessive collisionsBFCS errorsCruntsDlate collisions
考题
单选题Which statement is true about full-duplex Ethernet in comparison to half-duplex Ethernet?（）A
Full-duplex Ethernet consists of a shared cable segment. Half-duplex Ethernet provides a point-to-point link.B
Full-duplex Ethernet uses a loopback circuit to detect collisions. Half-duplex Ethernet uses a jam signal.C
Full-duplex Ethernet can provide higher throughput than can half-duplex Ethernet of the same bandwidth.D
Full-duplex Ethernet uses two wires to send and receive. Half-duplex Ethernet uses one wire to send and receive.
热门标签
最新试卷
