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TEST REPORTDVB-T to Cable ModulatorPromaxDigital To TV headend12-01/2010PROMAX DIGITAL TO TVThe perfect solution to distribute digitalsignals to a cable network in absoluteerror-free quality.Digital cable TV? This is easy!DVB-S is the standard for digital satellite TV. DVB-T - for digital terrestrial TV. AndDVB-C – for digital cable TV. So if you want to create the cable network to providedigital TV to a number of end users you need to equip all of them with DVB-C set-topboxes. You will also need the DVB-C headend. But is this the most cost effective way?The experts from Promax say: no, you can make it simpler and cheaper!36 TELE-satellite — Global Digital TV Magazine — 12-01/2010 — www.TELE-satellite.com

Promax guys were smartto notice that the modernTV-sets are more often thannot equipped with a DVB-Ttuner next to the classicalanalog one. And now, if theDVB-T signal can be transmitted over-the-air, it can betransmitted through a cablenetwork as well. The enduser’s TV-set does not careif the DVB-T signal comesto it from an aerial or froma cable system. Some of theviewers will have a DVB-Ttuner built-in in their flat TVsets, the others will use aseparate DVB-T set-top-boxTELE-satellite Worldwww.TELE-satellite.com/.Download this report in other languages from the wedishTurkish ﺍﻟﻌﺮﺑﻴﺔ añol ﻓﺎﺭﺳﻲ Français עברית r/promax.pdfAvailable online starting from 27 November 2009www.TELE-satellite.com — 12-01/2010 — TELE-satellite — Global Digital TV Magazine37

for terrestrial reception. Butone thing is certain: if theycan receive a wireless DVB-Tsignal they will also be ableto receive digital cable TVif only the cable headendoutputs DVB-T compatiblesignal. And Promax DigitalTo TV (DTTV) headend justdoes it! The system workswithout any additional settop-boxes installed at theend user side.into account when they wereTo make the cable networkattractive, you not only needto retransmit all the terrestrial signals available overthe air but you have to addcontent that is distributedvia satellites. Quite often youwould like to broadcast somecontent from A/V sources.For example, the hotels oftenplay looped information fortheir guests. Finally, you cannot forget about the Internetand the Internet TV (IPTV).Why not to make it availableto the cable subscribers aswell? All the above wishesare in fact the requirementsthat Promax engineers tookIt has a graphic LCD displaydesigning DTTV headend.ModulesdescriptionThe headend has a modular design so this is veryeasy to customize it accordingly to the specific needs.Everything is contained in astandard 19” rack. DT-800,the control unit and powersupply, is located leftmost.and a few buttons you useto control all modules. Additionally, there is an Ethernetconnector on the front panel.After connecting the moduleto the LAN, you are able todo all the settings more conveniently in a PC application.On the rear panel, we cansee the power socket, powerswitch, mains voltage selector, sockets for the controlcables and a cooling fan.In fact every module has aseparate fan. This is typicalinprofessionalheadends.The cooling fans create quitesome noise but one usuallydoes not install this stuff inthe room where people areexpected to work for hours.DT-800 is connected withevery other module with amulti wire cable. It can control up to 7 modules.Next module we had inthe test rack was DT-302.DT-302 is the double DVBS/S2 receiver with transportstream outputs. If you connect 2 LNB’s to its inputs,you can configure the unitto receive 2 different transponders.Eachsatellitereceiver has two identicaltransport stream ASI outputs. ASI means Asynchronous Serial Interface and isthe format of the transportstream transmission. DT-302enables us to select the programs we want to pass. Sowe do not have to retransmitevery channel from a giventransponder but only thechannels we want to show toour subscribers. Especiallyinteresting in this module arethe 2 CAM’s accessible aftera removal of the top cover. If38 TELE-satellite — Global Digital TV Magazine — 12-01/2010 — www.TELE-satellite.comyou insert a valid smart card,you will be able to descramble satellite channels! That’show the premium channelsare finding their way intocable networks.DT-102 was the next modulewe put next to DT-302. DT102convertstransportstreams into DVB-T signal. Itcan be any transport streambut in our test we used thestream from its neighbordescribed above: DT-302. Ithas two ASI-TS inputs andone DVB-T output. There are2 carriers (and thus 2 multiplexes) in the outputs ifonly we feed the unit with 2separate transport streams.The next module is DT-202, atwin DVB-S to DVB-T transmodulator. This modulesprovides the simplest andmost cost-effective solutionto distribute FTA satellitechannels, which of course donot require using any smartcard.As you can see on thephoto, DT-504 is the next

module. It has 4 A/V inputswhich must look very familiarto all our readers. Yes, theseare regular analog video andanalog stereo audio inputs.The signals may come fromDVD player, VCR, satellitereceiver, security camera orother source. Every of thoseanalog inputs is converted tothe separate digital channelat the output of this module.In this way, you get one DVBT carrier containing 4 channels.The last but one module,DT-212, is a DVB-T transmodulator. After receiving adigital terrestrial signal wecan shift it in the spectrum todifferent frequency. This canbe done to avoid some undesired interaction betweenthe signals in the network.Another important functionof this module is improvement of signal quality. Itdemodulates the signal, corrects erroneous bits and remodulates the signal back toDVB-T. As a result, we geta signal with very good C/Nratio suitable even for largecable network.for the password (PIN), andlater you just select themodule you want to configure (with right/left arrows).When the desired module isdisplayed, another ENTERallows you to start settingup the parameters. Up/downarrows change the valueof the digit or letter of thealphabetwhileleft/rightarrows change the positionin a number or name. Everything works very intuitively. When setting up theDT-302 you need to provide similar data to thosein the receiver installationmenu: LOF, frequency of thedesired transponder, band(C/Ku), LNB supply (13/18 V,22/0 kHz), standard (DVBS/S2), symbol rate. There isalso another option: servicelist. Once DT-302 locks tothe transponder, this submenu will list all recognizedservices (TV, radio and datachannels). You can markonly those services you wantto be included in the output. DT-102 converts 2 transport streams to two regular DVB-T COFDMsignals. You can see their spectrum on the photo. We set one of theirlevels 20 dB down. Otherwise, they would be equally strong. Even attenuated by 20 dB, the DVB-T signal hasexcellent quality. See the CBER, VBER, C/N andMER readings. 4 FUN.tv channel from HOTBIRDsatellite at 13 E re-modulated to DVB-Tand seen on the signal analyzer screen.Finally,therightmostmodule is DT-710. This isa combiner/amplifier thattakes up to 8 DVB-T carriers and outputs all of themin one cable. This would normally be an output for thecable network.InstallationRight after plugging inevery module and connectingthem on the rear panel withcontrol and signal cables,DTTV is ready for settingup. Though the number ofbutton is limited to six: fourarrows, ENTER and ESC, setting up the instrument is surprisingly easy. Right afterpower up, the DT-800 controlunit check what other unitsare connected to it. After afew seconds, we may pressENTER. Then you are asked40 TELE-satellite — Global Digital TV Magazine — 12-01/2010 — www.TELE-satellite.com

The remaining services willbe blocked. If the servicesare scrambled, you can usea valid smart card and insertit in the CAM installed inthe module. To get physical access to CAM, all youneed to do is to unscrew asmall lid on the top panel ofthe module. Actually, DT-302has 2 such modules – separate for every input.related to signal quality:MER, C/N, CBER, VBER areabsolutely excellent. Moreover, the signal level is veryhigh. When you connect amodern TV-set even at theend of a very large cablenetwork, the signal will stillbe very, very good. There isno single parameter we cancomplain about.Other modules are configured in the same manner.If the module has a DVB-Toutput, we need to selectthe DVB-T parameters: Frequency, Attenuation, FFTMode, Guard Interval, Constellation, Code Rate, andChannel Bandwidth.DTTV is a very high quality DVB-T headend of perfect output signal and verybig configuration possibility.The modules we had in ourtest rack are but a few ofthe modules available fromPromax. Visit their webpagewww.promaxelectronics.comfor more details. If you seriously think about the cableheadend and want to makethe whole enterprise economically sound, you haveto consider DTTV!As you can see, the numberof setting is rather high.If you just need to changeDVB-S transponder data, it isnot a problem. You can do itin no time. However if this isan initial setup, it may take awhile. To make it more convenient, Promax developedPC software to control DTTV.Both PC and DTTV mustfirst be connected to localarea network. You set the IPaddress, submask and gateway in DT-800 module manually. DHCP is not supported.This is something natural inprofessional equipment. Theapplication makes the wholeconfiguration process mucheasier. This is a real help forthe installer.Conclusion DTTV unit in the test configuration we had was able to generate 6 DVB-TCOFDM signals. Assuming that one can have 8-10 SDTV channels perevery carrier, one DTTV unit can give us 48-60 digital channels! Details of the satellite PATIO.TV channel converted to DVB-T.PerformanceThe quality of outputsignal is absolutely great.This is much, much betterthan you can get from thesatellite LNB or terrestrialantenna.That’sbecausethe modules have very goodfront ends, they demodulateDVB-S/S2 or DVB-T, correctthe bit errors and remodulate transport stream toDVB-T. Thanks to that, theoutput signal has practicallyno bit errors. All parameters Setting up DT 302 module. You can see setting the frequency of the transponder to be received anddemodulated to the pure transport stream.42 TELE-satellite — Global Digital TV Magazine — 12-01/2010 — www.TELE-satellite.com