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．continuousB．highC．lowD．discrete
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
相关考题：
● One feature of （74） is that it is possible to arrange for a singlemessage to be sent to a large number of other users simultaneously.（74）A. FaxB. IP telephoneC. Data ProcessingD. E-mail
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．smallB．highC．lowD．long
●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．smallB．highC．lowD．long(67) A．direct-sequenceB．discrete-sequenceC．duplicate-sequenceD．dedicate-sequence(68) A．dataB．byteC．packetD．bit(69) A．bitsB．frequenciesC．packetsD．messages(70) A．rateB．velocityC．bandwidthD．period
In the open systems interconnection (OSI) reference model, "layer" means one of seven conceptually complete,(71) arranged groups of services, functions, and protocols, that extend across all open systems.Application layer provides means for the application(72) to access the OSI environment. Presentation layer provides for the selection of a common syntax for representing data.(73) layer provides the means necessary for cooperating presentation entities to organize and synchronize their dialog and to manage their data exchange. Transport layer provides a reliable end-to-end data transfer service. Network layer provides for the entities in the transport layer the means for transferring blocks of data, by(74) and switching through the network between the open systems in which those entities reside. Data link layer provides services to transfer data between network layer entities. Physical layer provides the mechanical, electrical, functional, and procedural means to establish, maintain and(75) physical connections for transfer of bits over a transmission medium.A．ranklyB．levellyC．layeredD．hierarchically
When files are transferred between a host and an FTP server, the data is divided into smaller pieces for transmission. As these pieces arrive at the destination host, they must be reassembled to reconstruct the original file. What provides for the reassembly of these pieces into the correct order?A．The sequence number in the TCP headerB．The Start Frame. Delimiter in the 802.3 PreambleC．The TTL in the IP headerD．The acknowledgement number in the segment headerE．The frame. check sequence in the Ethernet frame. trailer
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．smallB．highC．lowD．long
An IP ( ) is a unique number the computer uses to identify itself, and to be identified over a network.A.addressB.deviceC.pointD.data
Which spread spectrum technology does the 802.11b standard define for operation()。 A.IRB.DSSSC.FHSSD.DSSS and FHSSE.IR, FHSS, and DSSS
The（）approach to language is to see it in terms of the bits and pieces by means of which it is put together.
Which statement is true about a worm attack？（）A、Human interaction is required to facilitate the spread.B、The worm executes arbitrary code and installs copies of itself in the memory of the infected computer.C、Extremely large volumes of requests are sent over a network or over the Internet.D、Data or commands are injected into an existing stream of data. That stream is passed between a client and server application.
Which value is NOT supported by Cisco Spectrum Expert， when checking for RF coverage？（）A、Access point received-signal strength levelB、Spectrum utilizationC、Client data rateD、In-band radio frequency interference
Which two statements correctly describe the relation between a data file and the logical databasestructures（）A、An extent cannot spread across data files.B、A segment cannot spread across data files.C、A data file can belong to only one tablespace.D、A data file can have only one segment created in it.E、A data block can spread across multiple data files as it can consist of multiple operating system （OS） blocks.
Which spread spectrum technology does the 802.11b standard define foroperation？（）A、IRB、DSSSC、FHSSD、DSSS and FHSSE、IR，FHSS，and DSSS
Which two statements are correct regarding multicast implementation using a WLAN controller (v5.2) and AP?（）A、Multicast traffic is sent out on Cisco APs at the highest mandatory data rate.B、Multicast traffic is sent out on Cisco APs at the highest supported data rate.C、On Cisco APs， multicast traffic and beacons are sent out at the same data rates to maintain a common cell size for normal data as well as multicast data.D、If there is more than one mandatory data rate， multicast traffic will be sent at the highest mandatory rate and beacons will be sent at the lowest mandatory rate.E、On Cisco APs， multicast traffic will be sent out at the highest data rate that a client can maintain with the AP.
You need to display a very large single-record data block. Since it will be so large, a convenient means of navigation is needed between items. Which type of canvas would you use to display the data block? （）A、Tab canvas. B、Pop up canvas. C、Spread table canvas. D、Vertical toolbar canvas.
单选题If voice and data traffic will be sent and received via a WAN links， what must be configured to provide a certain amount of dedicated bandwidth and to prioritize the voice traffic over other types of network traffic？（）AIPSec VPNBQoS mechanismCFirewallDNATEEIGRP routing protocolFStatic routing
多选题Which two statements correctly describe the relation between a data file and the logical databasestructures（）AAn extent cannot spread across data files.BA segment cannot spread across data files.CA data file can belong to only one tablespace.DA data file can have only one segment created in it.EA data block can spread across multiple data files as it can consist of multiple operating system （OS） blocks.
单选题According to the writer, the main feature of the revolution in office work over the last ten years is _____.Athe saving of time and moneyBthe use of computers in small companiesCthe wide use of word processorsDthe decreasing number of secretaries
单选题Which spread spectrum technology does the 802.11b standard define for operation（）。AIRBDSSSCFHSSDDSSS and FHSSEIR, FHSS, and DSSS
单选题Which statement is true about a worm attack？（）AHuman interaction is required to facilitate the spread.BThe worm executes arbitrary code and installs copies of itself in the memory of the infected computer.CExtremely large volumes of requests are sent over a network or over the Internet.DData or commands are injected into an existing stream of data. That stream is passed between a client and server application.
单选题The（）provides a rapid means of tallying when items of the same commodity are being loaded or unloaded in uniform drafts consisting of an equal number of pieces.Aunit methodBblock methodCstraight methodDpackage method
单选题“The city grew outward instead of upward” (Para. 2) means _____.Athe city became more spread out instead of growing tallerBthere were fewer small houses than tall buildingsCrapid development took place in the city centerDmany tall buildings could be found in the city