Unit18DigitalTelevisionTextKeywordsTechnicaltermsExpressionsNotestothetextText

Televisionisthemostwidespreadformofcommunicationintheworld.Itisasystemofsendingandreceivingpicturesandsoundbymeansofelectronicsignalstransmittedthroughwiresandopticalfibersorbyelectromagneticradiation.Televisionhasavarietyofapplicationinsociety,business,andscience.Themostcommonuseoftelevisionisasasourceofinformationandentertainmentforviewersintheirhomes.

Overthepastyears,digitaltechnologyhasrapidlychangedtheworldwelivein.Itchangesthewaywecommunicate,thewaywedobusinessandthewaywelearn.Bywayofexample,theapplicationofdigitaltechnologytoourtelephoneservicehasnotonlyimprovedthequalityofservicebuthasalsoenabledthedevelopmentofvalue-addedservicessuchasinteractiveenquiryandphone-bankingservices.Withtheforthcomingthirdgenerationmobilephonetechnology,evenmultimediaservicescanbeprovided.Thetraditionaltelevisionsetwillbeturnedintoamultifunctionalmediareceiver,meetingvariousdemandsofusers.ChinalauncheditscableTVnetworkplanin2003,andwillstartdigitalsatelliteservicesin2005.Bytheyear2008,digitaltechnologieswillbeintroducedtomostpartsofthecountry.

WhatisDigitalTelevision(DTV)?

Atpresent,ourterrestrialtelevisionservicesaretransmittedinanalogueforms.Analoguetransmissiontechnologyconvertssoundandpicturesintocontinuouslyvaryingelectricsignalswhich,aftertransmission,areconvertedbacktosoundandpicturesbytelevisionsets.

Digitaltelevisionreceivers,whichconverttheanalog,orcontinuous,electronictelevisionsignalsreceivedbyanantennaintoanelectronicdigitalcode(aseriesofonesandzeros),arecurrentlyavailable.Theanalogsignalisfirstsampledandstoredasadigitalcode,thenprocessed,andfinallyretrieved.ThatmeansDTVisanewwayoftransmittingtelevisionservices.Soundandpicturesareprocessedelectronicallyintodigitalsignals,whicharethentransmittedasabitstreamandreconvertedbydigitalTVsetsorappropriateset-topboxesintotelevisionprogrammes.

Thismethodprovidesacleanersignalthatislessvulnerabletodistortion.Thedifferenceinqualitybetweendigitaltelevisionandregulartelevisionissimilartothedifferencebetweenacompactdiscrecording(usingdigitaltechnology)andanaudiotapeorlong-playingrecord.

BenefitsofDTV

ThebenefitsofDTVaremanifold.

(1)?Efficientutilizationofbandwidth.

Atpresent,usinganaloguetechnology,awholefrequencychannelisneededforcarryingonetelevisionprogram.Byusingvideocompressiontechnology,DTVenablesseveraltelevisionprogramstobedigitallycombinedbeforetheyarecarriedonthesamefrequencychannel.Thiswillsignificantlyimprovespectrumefficiency,thusenablingtheprovisionofwiderprogrammingchoicewithinthesamebandwidth.

(2)?Betterpictureandsoundquality.

Undertheanalogueenvironment,televisionsignalsaresubjecttointerferencebyothersignalsourcessuchaspowerline,reflectionsfrombuildings,etc.Thereceptionqualityisthereforelessthanideal.Asdigitalsignalsaremorerobustthananalogueones,consumerswouldbeabletogetmuchbettersoundandpicturequalitythroughDTV.Inaddition,DTVenablestheprovisionofHighDefinitionTelevision(HDTV)whichdeliverscinema-qualitypicturesandCD-qualitysound.Alsomorechannelchoiceswillbeprovided.

(3)?Innovativeservices.

AsDTVcantransmitTVprogramsaswellasdata,viewerswillbeabletoreceivenotonlyTVbutalsoavarietyofinteractive,multi-mediaservicesthroughDTV.E-commerceonTVwillbeoneofthemanynewcommercialopportunitiesthattheindustrymayexplore.

(4)?Government’spolicyinitiatives.

OneoftheinitiativesoftheDigital21InformationTechnologyStrategyistocreateanenvironmentconducivetotheflourishingoftelevisionmarket,introductionofinnovativeservicesandpromotionofHongKongasaleadingregionalbroadcastinghub.Keywords

electromagnetic

adj.電磁的

radiation

n.輻射，放射

enquiry n.詢問

multifunctional adj.多功能的

cable

n.電纜

terrestrial adj.陸地

sample vt.取樣，采樣

retrieve v.重新得到

vulnerable adj.易受攻擊的，易受…的攻擊

audiotape n.錄音磁帶

utilization

n.利用

interference

n.干擾，干涉

reflection n.反射

robust adj.精力充沛的

innovative adj.創(chuàng)新的，革新(主義)的

initiative n.主動

flourishing adj.繁茂的，繁榮的，欣欣向榮的Technicalterms

DigitalTelevision(DTV) 數(shù)字電視

opticalfiber 光纖

electromagneticradiation 電磁輻射

value-addedservices 增值服務(wù)

phone-bankingservices 電話銀行服務(wù)

mobilephonetechnology 移動電話技術(shù)

set-topboxes(電視上) 機頂盒

E-commerce 電子商務(wù)Expressions

bymeansof… 借助于…

aseriesof 一系列

besimilarto… 與…相似Notestothetext

1.?Itisasystemofsendingandreceivingpicturesandsoundbymeansofelectronicsignalstransmittedthroughwiresandopticalfibersorbyelectromagneticradiation.

它是一個利用電線、光纖或電磁輻射發(fā)射的電信號來發(fā)送和接收圖像與聲音的系統(tǒng)。本句的主干為“Itisasystemof…”，可解釋為“這是一個…的系統(tǒng)”；“bymeansof…”引導(dǎo)方式狀語；“transmittedthrough…”至句末為定語后置，修飾前面的“signals”。

2.?Digitaltelevisionreceivers,whichconverttheanalog,orcontinuous,electronictelevisionsignalsreceivedbyanantennaintoanelectronicdigitalcode(aseriesofonesandzeros),arecurrentlyavailable.

數(shù)字電視接收機可將通過天線接收到的模擬的