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  1. 1. TEST REPORT DVB-T to Cable Modulator 12-01/2010 Promax PROMAX DIGITAL TO TV The perfect solution to distribute digital signals to a cable network in absolute error-free quality. Digital To TV headend Digital cable TV? This is easy! DVB-S is the standard for digital satellite TV. DVB-T - for digital terrestrial TV. And DVB-C – for digital cable TV. So if you want to create the cable network to provide digital TV to a number of end users you need to equip all of them with DVB-C set-top- boxes. 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 —
  2. 2. Promax guys were smart to notice that the modern TV-sets are more often than not equipped with a DVB-T tuner next to the classical analog one. And now, if the DVB-T signal can be trans- mitted over-the-air, it can be transmitted through a cable network as well. The end user’s TV-set does not care if the DVB-T signal comes to it from an aerial or from a cable system. Some of the viewers will have a DVB-T tuner built-in in their flat TV- sets, the others will use a separate DVB-T set-top-box TELE-satellite World Download this report in other languages from the Internet: Arabic ‫ﺍﻟﻌﺮﺑﻴﺔ‬ Indonesian Indonesia Bulgarian Български Czech Česky German Deutsch English English Spanish Español Farsi ‫ﻓﺎﺭﺳﻲ‬ French Français Hebrew ‫עברית‬ Greek Ελληνικά Croatian Hrvatski Italian Italiano Hungarian Magyar Mandarin 中文 Dutch Nederlands Polish Polski Portuguese Português Romanian Românesc Russian Русский Swedish Svenska Turkish Türkçe Available online starting from 27 November 2009 — 12-01/2010 — TELE-satellite — Global Digital TV Magazine 37
  3. 3. for terrestrial reception. But into account when they were does not install this stuff in you insert a valid smart card, one thing is certain: if they designing DTTV headend. the room where people are you will be able to descram- can receive a wireless DVB-T expected to work for hours. ble satellite channels! That’s signal they will also be able Modules DT-800 is connected with how the premium channels to receive digital cable TV every other module with a are finding their way into description if only the cable headend multi wire cable. It can con- cable networks. outputs DVB-T compatible The headend has a modu- trol up to 7 modules. signal. And Promax Digital lar design so this is very DT-102 was the next module To TV (DTTV) headend just easy to customize it accord- Next module we had in we put next to DT-302. DT- does it! The system works ingly to the specific needs. the test rack was DT-302. 102 converts transport without any additional set- Everything is contained in a DT-302 is the double DVBS/ streams into DVB-T signal. It top-boxes installed at the standard 19” rack. DT-800, S2 receiver with transport can be any transport stream end user side. the control unit and power stream outputs. If you con- but in our test we used the supply, is located leftmost. nect 2 LNB’s to its inputs, stream from its neighbor To make the cable network It has a graphic LCD display you can configure the unit described above: DT-302. It attractive, you not only need and a few buttons you use to receive 2 different trans- has two ASI-TS inputs and to retransmit all the terres- to control all modules. Addi- ponders. Each satellite one DVB-T output. There are trial signals available over tionally, there is an Ethernet receiver has two identical 2 carriers (and thus 2 mul- the air but you have to add connector on the front panel. transport stream ASI out- tiplexes) in the outputs if content that is distributed After connecting the module puts. ASI means Asynchro- only we feed the unit with 2 via satellites. Quite often you to the LAN, you are able to nous Serial Interface and is separate transport streams. would like to broadcast some do all the settings more con- the format of the transport The next module is DT-202, a content from A/V sources. veniently in a PC application. stream transmission. DT-302 twin DVB-S to DVB-T trans- For example, the hotels often On the rear panel, we can enables us to select the pro- modulator. This modules play looped information for see the power socket, power grams we want to pass. So provides the simplest and their guests. Finally, you can switch, mains voltage selec- we do not have to retransmit most cost-effective solution not forget about the Internet tor, sockets for the control every channel from a given to distribute FTA satellite and the Internet TV (IPTV). cables and a cooling fan. transponder but only the channels, which of course do Why not to make it available In fact every module has a channels we want to show to not require using any smart- to the cable subscribers as separate fan. This is typical our subscribers. Especially card. well? All the above wishes in professional headends. interesting in this module are are in fact the requirements The cooling fans create quite the 2 CAM’s accessible after As you can see on the that Promax engineers took some noise but one usually a removal of the top cover. If photo, DT-504 is the next 38 TELE-satellite — Global Digital TV Magazine — 12-01/2010 —
  4. 4. module. It has 4 A/V inputs for the password (PIN), and which must look very familiar later you just select the to all our readers. Yes, these module you want to config- are regular analog video and ure (with right/left arrows). analog stereo audio inputs. When the desired module is The signals may come from displayed, another ENTER DVD player, VCR, satellite allows you to start setting receiver, security camera or up the parameters. Up/down other source. Every of those arrows change the value analog inputs is converted to of the digit or letter of the the separate digital channel alphabet while left/right at the output of this module. arrows change the position In this way, you get one DVB- in a number or name. Eve- ■ DT-102 converts 2 transport streams to two regular DVB-T COFDM T carrier containing 4 chan- rything works very intui- signals. You can see their spectrum on the photo. We set one of their levels 20 dB down. Otherwise, they would be equally strong. nels. tively. When setting up the DT-302 you need to pro- The last but one module, vide similar data to those DT-212, is a DVB-T trans- in the receiver installation modulator. After receiving a menu: LOF, frequency of the digital terrestrial signal we desired transponder, band can shift it in the spectrum to (C/Ku), LNB supply (13/18 V, different frequency. This can 22/0 kHz), standard (DVB- be done to avoid some unde- S/S2), symbol rate. There is sired interaction between also another option: service the signals in the network. list. Once DT-302 locks to Another important function the transponder, this sub- of this module is improve- menu will list all recognized ment of signal quality. It services (TV, radio and data ■ Even attenuated by 20 dB, the DVB-T signal has demodulates the signal, cor- channels). You can mark excellent quality. See the CBER, VBER, C/N and MER readings. rects erroneous bits and re- only those services you want modulates the signal back to to be included in the output. DVB-T. As a result, we get a signal with very good C/N ■ 4 channel from HOTBIRD satellite at 13°E re-modulated to DVB-T ratio suitable even for large and seen on the signal analyzer screen. cable network. Finally, the rightmost module is DT-710. This is a combiner/amplifier that takes up to 8 DVB-T carri- ers and outputs all of them in one cable. This would nor- mally be an output for the cable network. Installation Right after plugging in every module and connecting them on the rear panel with control and signal cables, DTTV is ready for setting up. Though the number of button is limited to six: four arrows, ENTER and ESC, set- ting up the instrument is sur- prisingly easy. Right after power up, the DT-800 control unit check what other units are connected to it. After a few seconds, we may press ENTER. Then you are asked 40 TELE-satellite — Global Digital TV Magazine — 12-01/2010 —
  5. 5. The remaining services will related to signal quality: be blocked. If the services MER, C/N, CBER, VBER are are scrambled, you can use absolutely excellent. Moreo- a valid smart card and insert ver, the signal level is very it in the CAM installed in high. When you connect a the module. To get physi- modern TV-set even at the cal access to CAM, all you end of a very large cable need to do is to unscrew a network, the signal will still small lid on the top panel of be very, very good. There is the module. Actually, DT-302 no single parameter we can has 2 such modules – sepa- complain about. rate for every input. Conclusion ■ DTTV unit in the test configuration we had was able to generate 6 DVB-T Other modules are config- DTTV is a very high qual- COFDM signals. Assuming that one can have 8-10 SDTV channels per every carrier, one DTTV unit can give us 48-60 digital channels! ured in the same manner. ity DVB-T headend of per- If the module has a DVB-T fect output signal and very output, we need to select big configuration possibility. the DVB-T parameters: Fre- The modules we had in our quency, Attenuation, FFT test rack are but a few of Mode, Guard Interval, Con- the modules available from stellation, Code Rate, and Promax. Visit their webpage Channel Bandwidth. for more details. If you seri- As you can see, the number ously think about the cable of setting is rather high. headend and want to make If you just need to change the whole enterprise eco- DVB-S transponder data, it is nomically sound, you have not a problem. You can do it to consider DTTV! ■ Details of the satellite PATIO.TV channel converted to DVB-T. in no time. However if this is an initial setup, it may take a while. To make it more con- venient, Promax developed PC software to control DTTV. Both PC and DTTV must first be connected to local area network. You set the IP address, submask and gate- way in DT-800 module manu- ally. DHCP is not supported. This is something natural in professional equipment. The application makes the whole configuration process much easier. This is a real help for the installer. Performance The quality of output signal is absolutely great. This is much, much better than you can get from the satellite LNB or terrestrial antenna. That’s because the modules have very good front ends, they demodulate DVB-S/S2 or DVB-T, correct the bit errors and remodu- late transport stream to DVB-T. Thanks to that, the output signal has practically ■ Setting up DT 302 module. You can see setting the frequency of the transponder to be received and no bit errors. All parameters demodulated to the pure transport stream. 42 TELE-satellite — Global Digital TV Magazine — 12-01/2010 —
  6. 6. Expert Opinion TECHNICAL + DATA Manufacturer Promax Electronica, S.A., Barcelona, Spain Very flexible configuration. Simple user inter- face. Extremely good and strong output signal. No Internet DVB-C set-top-boxes needed at the customer side. Phone +034 93 260 20 02 Fax +034 93 338 11 26 - Jacek Pawlowski Model Digital To TV TELE-satellite Some functionalities of the regular DVB-C Test Center Poland Description DVB-T headend for cable networks (SMATV) (like the return channel) are impossible. Also the number of possible digital channels is lower than Inputs DVB-S/S2, DVB-T (e.g. from the aerial), A/V analog, IPTV, TS-ASI in DVB-C (but this is important only if you need to supply more Output DVB-T COFDM than about 200 channels). Power supply 120/240 V 50/60 Hz ■ Screenshot of DTTV control application. ■ DT-302 module has 2 CAM’s accessible from the top after removing a ■ Green LED’s indicate that DT-302 has locked to the satellite transponder cover. They are capable to decipher scrambled channels. Of course, you and that DT-102 outputs correct DVB-T signal. need to put in valid smart cards. — 12-01/2010 — TELE-satellite — Global Digital TV Magazine 43