O meu Carrinho está vazio



DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN
No. 42/2009 (Dec. 14, 2009)
DVB-T2 approved, but what about its future? The decision on digitalization of terrestrial television signals in Europe was made at the end of the nineties. Since then, DVB consortium has been established (Digital Video Broadcasting), also in charge of DVB-T project (Terrestrial). The pioneer in this respect was the United Kingdom which already in 1997 launched first test transmitters.
What has changed in the last 12 years?
Almost all European countries have transition schedules and most of them have completed the first stages of implementation of terrestrial multiplexes. Some countries, such as Finland and Sweden, have already forgotten what is analog television, after termination of analog broadcasting in so-called ASO process (Analog Switch Off).
In 2006, due to technological development and a tendency to save transmission bandwidth, the DVB consortium began to work on a second version of the standard - DVB-T2.
In September this year, the work on the new standard has been completed and the European Telecommunications Standards Institute (ETSI) issued an official publication.
"T" with the number "2" is characterized by different encoding, use of a higher number of subcarriers, and above all - replacement of 64-QAM by 256-QAM modulation, which translates to nearly a doubling of throughput, or otherwise, reducing bandwidth usage (more programs within a multiplex).
The DVB-T2 transmitter on the Winter Hill in England - here it starts...
The testing ground for DVB-T2, similarly to DVB-T, has become the United Kingdom, where test broadcasts began in 2008. Only a few days ago, on December 2, analog TV was switched off in the region of North West England (Granada), and the world's first official DVB-T2 broadcasting has started.
In early 2010, the multiplex is to launch 4 High Definition channels. It would not be possible in the case of DVB-T (up to two HD channels in one multiplex). According to the British, 50% of the population should be able to watch the June's World Cup in South Africa in high resolution.
The next countries which will certainly join the UK are the Nordic countries. NorDig - the operator responsible for the process of digitalization of television in Denmark, Finland, Iceland, Norway and Sweden - has recently published requirements for DVB-T2 receivers, although these countries still use the first version of the DVB-T standard.

It would seem that the answer to the question posed at the beginning of the article is obvious. However, the problem is that - outside the pioneer countries: the UK, Scandinavia, and the Czech Republic - there are no quick plans to launch the second version of the standard, and all efforts are focused on the planned switchover to digital terrestrial television.
In a few years, when the process of digitalization in Europe will be completed, DVB-T2 may be difficult to implement in countries using the older version due to market reasons. Additionally, more attractive alternatives will include new concepts such as DVB-T3, UHDTV (Ultra High Definition Television - offering resolution up to 16 times higher than Full HD), or three-dimensional television.
Another issue is the economic aspect of the introduction of the DVB-T2. Example of France has clearly shown that the DVB-T still offers many opportunities. Currently, the country's viewers can watch 5 HD channels, and, by 2015, this figure will increase to 18 (adequate range of frequencies has already been allocated).
The next year or two will show the direction which Europe is taking. It is possible that the EU will issue a directive establishing a common standard in all member states. In that case the DVB-T2 seems to be more versatile than its predecessor. Otherwise, each country acting on its own may have a different system of digital broadcasting.
From which tower can you see the building and another tower? In the photos below you can see a television tower and an unusual building. The building has 88 floors and is 452 meters high, from 1998 to 2004 it was the highest building in the world. It was designed by Argentine architect César Pelli.
Due to the unusual design of the building, the construction was entrusted to two companies that entered in a kind of building race. The competition was won by Samsung Constructions, despite the fact that the company began operations a month later than the competitor - Hazama company of Japan.
What is the name of the building and from which tower it can be seen best? Answer at the end of this issue.
What is the name of the building and from which tower it can be seen best? - Answer at the end of this issue.
(Photos by Jerzy Babula)
Multi-standard modulators with microprocessor control. DIPOL offers now double-sideband modulators - MT41 R871741, MT42 R871742, and MT47 R871747 - from the new "Cabrio Line" launched by TERRA company.
The modulators are characterized by a number of innovative solutions, stable parameters and reliable operation. They can be successfully used both in home antenna installations as well as in small-sized MATV systems.
The modulators have a microprocessor control - the choice of output channel is performed with two buttons (after opening the top cover). The channel number or any changeable parameter is displayed on the LED display and stored in a non-volatile memory. Use of quartz-stabilized PLL practically eliminates frequency error. There is a possibility to protect the modulator against unauthorized change of the preset parameters (with an appropriate button sequence).
The modulators can be connected in cascade. Their RF signals can be combined with terrestrial TV channels (it requires to match the levels of terrestrial TV signals with the RF output levels of the modulators, as well as to ensure adequate frequency spacing).
The video input frequency range (of the baseband video signal) is 20 Hz - 6 MHz, audio input frequency range: 20 Hz - 15 kHz. The output frequency range (from which the user can select suitable RF channel) is dependent on the model. MT41 covers 470-862 MHz (UHF band), MT42: 170-300 MHz (VHF 3 and "Superband"), MT47 - both the ranges.
The audio subcarrier is switchable among many PAL versions: 4.5 MHz, 5.5 MHz, 6 MHz, and 6.5 MHz. The video carrier can be fine-tuned within +/- 2.25 MHz range (step 0.25 MHz). A/V ratio is switchable between 12 dB and 16 dB. The typical RF output level is 90 dBuV (MT41) or 85 dBuV (MT42, MT47). It can be reduced even by 20 dB. The standard deviation of the audio carrier (+/-50 kHz) can be achieved for maximum input signal levels from 150-775 mV RMS (15 dB range). The input baseband video signal should be kept at the level of 1 Vp-p +/-1 dB.
TV Modulator TERRA MT41
View of the MT41modulator
How to make use of DLNA function? In the market, there are televisions equipped with LAN ports, which can use Ethernet connection for cooperation with other equipment having DLNA (The Digital Living Network Alliance) certificate.
The DLNA standard can be implemented in televisions, PVRs, DVRs, cellular phones, NAS drives, hi-fi systems, PCs, palmtops, network printers. After connecting such a TV to the home computer network, the users get access to the multimedia contained in the home archive, phones etc.
DLNA certified devices allow to play multimedia shared by the server, which can be any PC running appropriate software. The TVs are capable of displaying photos, decoding video streams (movies), and playing music.
The diagram below is a proposal to create a digital multimedia center without a need of buying special multimedia server.
Offset Satellite Dish: 90cm, galv. paint. A-EFull Band LNB: Golden Interstar GI-201 (0.3 dB) UHF TV Antenna: DIPOL 16/21-69 DVB-TTV/SAT Combiner - Splitter RS-02M DCTVSubscriber Terminal Outlet: Signal TV-FM-SAT/RJ-45/RJ-11DVB-T Receiver: FERGUSON FT-8100 HDDVB-S/DVB-S2 Receiver: OPTICUM 9500 HD PVR 2CI 2CX E PlusAccess Point 802.11n (draft 2.0): TP-Link TL-WR941N <br />(300Mbps, built-in router and 4-port switch)E1015E1015
The home network enabling reception of digital television (DVB-T/DVB-S/DVB-S2) and distribution of multimedia
The TV/SAT combiner-splitter R85312 allows to send terrestrial and satellite signals via one cable. They are separated by the Signal outlet R694043, supplying signals to the A99259 - DVB-T receiver and A99435 - DVB-S2 receiver.
The R694043 outlet is equipped with RJ45/RJ11 connectors, which can be used for cooperation with an access point located nearby the TV. Of course the UTP cabling should be be connected to the RJ45 socket.
Due to wide bandwidth required for multimedia transmissions, a good solution is to use access points compatible with the newly ratified n standard. In this case the transmission speed can reach up to 300 Mbps. An example is the AP TP-Link N3251.
Color cameras in various lighting conditions. As regards the capabilities of color cameras to operate in various lighting conditions, they can be divided into several groups:
  • Color cameras with built-in fixed IR filters - they are not dedicated for night operation. The filter blocks the negative influence of the infrared part of daylight on the quality of the images, which can guarantee true colors, but the cameras cannot operate with IR illuminators.
  • Suitable for use in good light conditions. Examples: u-cam 110 M1128 and CAM 412D M10730.
Color CCTV Camera: U-cam 110 (without lens)
Ceiling Color Camera: CX-412D (with lens)
Color cameras with built-in fixed IR filters
  • Day/night cameras - they do not use IR filters so they can operate at night (even in total darkness, without visible light) with the use of IR illuminators. Such constructions, however, have slight disadvantages. In normal lighting conditions (visible light) the cameras sometimes have problems with white balance - they do not render the actual colors, so, for example, black is often "seen" as a dark blue, etc. The effect is more apparent when they work outside, where the natural light includes solar infrared radiation. In indoor areas with artificial light (bulbs, fluorescent lamps), the phenomenon is not so visible. The examples of the cameras are VF-515 M11278 and V-CAM 515 M10751.
Outdoor Color CCTV Camera: VF-515 IR/B<br /> (with 4-9 mm varifocal lens and IR illuminator)Outdoor Color CCTV Camera: VF-515 IR/B<br /> (with 4-9 mm varifocal lens and IR illuminator)
Vandal Proof CCTV Camera: V-CAM 515 + IRVandal Proof CCTV Camera: V-CAM 515 + IR
Day/night cameras
  • Cameras with mechanically switching IR filter - they eliminate the problems with faithful color reproduction. These cameras are more expensive, but the image quality is very good both during the day and at night. They should only be used with lenses designed for cooperation with IR illuminators. The examples of the cameras include SN-FFXP3200MIR M10790 and SN-586C/B WDR M11208
Cameras with mechanically switching IR filter
CCTV DVRs - the power issues. DVRs should be powered from single-phase 3-wire TN-S power networks (IEC 60364): phase (L) - neutral (N) - protective earth (PE). If the local power network does not have PE wire (usually green-yellow) connected to the earthing pin of the power socket, the proper solution in grounding the housing of the DVR. Any alteration in the power network can be done only by a licensed electrician, not only because of the danger of electric shock during such operations, but also because not all neutral and grounding circuits fulfill technical requirements necessary for effective protection (measurements needed).
Failure to comply with these requirements is the most common cause of damaging the DSP processor, which reveals in lack of isolation between individual channels or other strange effects, or lack of operation of video inputs.
In addition , to protect DVRs it is recommended to use video separators, especially when cameras and the DVR are powered from different phases.
In installations where coaxial cables run near the electricity network or the cameras are powered from switched power supplies or when the installation is exposed to lightning - it is recommended to use video surge protectors.
Correct power connection of ULTIMAX DVR
Modern system of monitoring dorms. Maisel SudParis is an non-profit organization whose main mission is to provide accommodation for students of two prestigious French universities: "Telecom SudParis" and "Telecom Ecole de Management" (former INT). The campus located in Evry consists of six buildings with single rooms, studios, apartments, common living areas such as kitchens, dining rooms, laundry rooms, meeting rooms.
In order to counteract vandalism committed on the open access equipment, the administrator decided to install video surveillance system. The system will be launched in February 2010.
It will consist of 106 vandal-proof ACTi cameras integrated by managing and recording software (NVR) - domes with standard resolution (CAM-7321 K1311) and megapixel cameras ACM-7411 K1313. IP technology allows for simple construction of the large system and provides effective management tools. High resolution of the cameras increases the effectiveness of the fight against pathological behavior. Vandal proof housings of the cameras are ideal for such applications - the cameras can operate without fear of being damaged.
After startup of the system the investor expects a significant reduction of vandalism and petty crime.
Basic system architecture of the IP CCTV system
RJ-45 wiring schemes. Improper installation of RJ-45 connectors is the reason of many failures. The diagrams below show the proper connections of wires in Ethernet cables.
There are two basic standards for 100Base-T networks:
  • T568B (more popular)
  • T568A
In the case of identical connections on both sides we get a "straight-through" cable. Applying two different standards on the sides we have "crossover" cable.
To connect a computer to a switch (hub, router) we use "straight-through" cable, but computer - computer connections usually require "crossover" cable.
T568A standard - "straight-through" cable
T568B standard - "straight-through" cable
"Crossover" cable - on one end connected according to T568B, on the other - T568A. This kind of cable usually connects two computers.
The modular plugs can be crimped with NS-210 8P8C/RJ-45 E7905 tool. We recommend to test connections with RJ-45/RJ-11 cable tester N7055.
Crimping Tool NS-210 <br />(for 8P8C modular plugs)
Cable Tester (RJ-45, RJ-11)
Crimping Tool NS-210 (for 8P8C modular plugs)
Cable Tester (RJ-45, RJ-11)
One of the most important elements of the network is the transmission cable. UTP/FTP cables should be made of high quality materials, the pairs and the bundle have to be carefully twisted to minimize crosstalk. Installers will appreciate the flexibility of the cable allowing easy installation in ducts. Proper selection of materials and standard size have an impact on the ease of installing RJ-45 connectors. The example of a top-quality UTP cable is NETSET E1408, with parameters far exceeding the requirements for Category 5e twisted pair cables. It can be used at maximum lengths acceptable for this kind of cabling.
CAT 5e UTP Cable: NETSET BOX [305m]<br /> (for indoor applications)
NETSET BOX UTP 5e - indoor UTP cable
Petronas Twin Towers. Twin towers in the Malaysian capital Kuala Lumpur, constructed from 1992 to 1998. Samsung and Hazama competed building individual towers. At the level of 41 and 42 floors the towers have been connected by a corridor with a length of 58 m. They are still the world's tallest twin building.
The TV tower from which you can see the twin towers and the panorama of the city is Menara Kuala Lumpur, with a height of 421 m.
The panorama of Kuala Lumpur and view of Menara Kuala Lumpur tower
We have written about:

LNB skew adjustment. When installing a satellite system it is important to set appropriate skew (or polarization) angle of the LNB. The angle depends on the satellite and geographical location of the site. ... It optimizes the cross-polarization isolation between signals of vertical and horizontal polarizations, and has strong influence on quality of digital signal...
- archive DWR of March 10, 2008

Problems in large multiswitch systems. In large multi-family buildings there are the following problems that should be taken into consideration when installing SMATV systems:
  • unequal distances between multiswitches and outlets - the reason of different signal levels in the outlets,
  • the long distances of the cables between multiswitches and outlets are the reason of large and changeable (with frequency) attenuation of the signals,
  • unequal distances between staircases - the reason of considerable signal level differences among the subnetworks.
Modern multiswitches from Terra allow to overcome these problems. The MSR-xxx series and its complementary line - MSV-xxx (without AC/DC adapter) allow to build large multiswitch systems up to 300 outlets.
- archive DWR of May 12, 2008

ULTIAIR - ideal devices for transmission of video data. Installation of a classical video surveillance system in a functioning parking lot is expensive and time-consuming. Usually, it also temporarily excludes some parts of the area from normal service. A modern and safe solution to the problems is wireless transmission. Application of ULTIAIR devices allows to install IP surveillance system very quickly...
- archive DWR of Feb. 16, 2009

Index of published issues
Se esta interessado em receber a nossa Newsletter semanal por email, insira o seu endereço de email: