DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN

MPEG-4. The race has started. Transmission of multimedia, especially video data, is both the problem and mainstream of telecommunications of the future. Video transmission requires high throughputs of the links, which should continuously grow due to higher and higher quality requirements. Every kind of transmission (satellite and terrestrial radio links, cable infrastructure, streaming) imposes bandwidth limitations, so the key issue is efficient data compression.
As an example, the popular satellite transmission protocol DVB-S/MPEG-2 (38 Mbps) allows transmission of 7 SDTV programs, whereas DVB-S2/MPEG-4/AVC system ensures transmission of 26 SDTV or 6 HDTV programs - all from one satellite transponder.
Stream transmission is still quite limited. Quick development of IPTV meets the barriers of typical throughputs of the most popular links, even on the most developed markets (e.g. Hong Kong - 5 Mbps, USA - 2Mbps). So when MPEG-4/AVC ensures 2 times higher compression level than MPEG-2, the choice is obvious.
MPEG-4/AVC will also solve the problem of the required spectrum for terrestrial transmission of HDTV programs.
Due to mass production of the codecs, license fees can reach billions of dollars. Currently the leader of second-generation codecs is still MPEG-4/AVC. But there are two serious competitors that would like to share the profits: WMV codec (VC-1 standard used in Xbox) developed by Microsoft, and Chinese AVS.

IPTV will allow to crate both global TV networks and selective services for small groups (e.g. educational TV) - the condition of its mass development is simultaneous improvement of network capacity and compression methods.

Where is the tower? The construction below has been raised at the foot of the Heavenly Mountains. The peak of the highest mount is at 7439 m above see level. Permanent snow and glaciers cover the areas of the chain above 4000 m.
This tower, 372 m high, has been built on the slope of the Blue Hill, near Almata - the city name can be translated as "Reach in Apples". The country is sometimes considered European state, despite the fact that only ca. 5% of its area lies in Europe.
What country are we talking about? The answer can be found in the end of the issue.

TV tower at the foot of the Heavenly Mountains (by Maria Blackwood)

Community/MATV systems - reception of channels with different levels. It is common situation that some channels are much weaker than the rest. It would be a mistake to increase gain in such installation using broadband amplifiers. To ensure proper reception of the weak channels (e.g. input level 40 dB), they should be amplified by 40 dB, which would proportionally raise levels of the stronger ones (e.g. up to 120 dBuV). Such high levels usually cause intermodulation distortions that mainly spoil the weak channels. A satisfactory solution is only obtained by employing channel amplifiers.
Using channel amplifiers it is possible to even out the levels of individual channels. This method allows to optimize conditions of work of amplifiers in the installation as well as provides best possible parameters of signals delivered to TV sets. For use in middle and big size installations we advise to employ ZG series (amplifiers ZG-401 R90517 and ZG-601 R90538), that are characterized by very strong attenuation out of working band, excellent matching, very high output level and low S/N ratio.
Channel amplifiers are indispensable in all installations where differences of input signals exceed 20 dB (it is impossible to get good results with broadband amplifiers).

The signals at antenna terminals.

Channel amplifier enables the installer to adjust level of specific channel (in the example: 108 dBuV for channel 31 - permissible level within installation providing 8 channels). On the left and right - excessive levels that would be produced by broadband amplifier.

Set of ZG channel amplifiers from Alcad

IP CCTV gains popularity in monitoring of houses. Until quite lately the cost of video server being a part of every IP camera was so high that the cameras were only used in big surveillance systems, e.g. in city monitoring.
Growing popularity of IP CCTV is the reason of quick downward movement and IP devices become accessible for anyone who wishes to monitor house, small business etc.
Taking into consideration supplementary costs of cabling and possible expansion of the installation in the future, it may be even cheaper to build IP-based system. Such a system can also be supported by advanced software solutions.

IP camera ACTi ACM-33211 K1312

IP cameras in marketing - Pixord line. IP cameras are often used for presentation of towns, cities, hotels, ski slopes, beaches.Example installations:

• city promotion
- For presentation of images in the Internet there may be used (often previously installed) analog CCTV cameras. Such a camera is linked to video server P1401 K2131. If dedicated installation is to be used, the best solution is the camera P400 K1131 or its wireless equivalent P400W K1132. For example, in the particular case of Bochnia town it has been used video server P1401 (connected to existing analog CCTV system). The installation has been carried out by the company F.H.P.U. Kosecki.
Market square of Bochnia.

• hotel promotion
- In this case there may also be utilized existing analog cameras. The images available on the website are provided by video server P1401 K2131, due to stream transmission with MPEG-4 compression transmission. The stream is at the same time recorded with ADACS card.
The installation has been carried out by the company P.H.U VOLTA.Hotel Dziki Potok

Intercom system for housing society in Opole. The investor demanded that the panels should be installed at the main gate and three additional internal gates to the parts of the real estate.
The contractor - TV Integra company - chose digital system from Alcad, based on MAN-080 unit.
The main reason for the choice was high quality of voice transmission, much better than of other solutions, and performance of the handsets and panels.
The implemented system allows identification of the calling gate and its opening without unlocking other gates. The digital system of Alcad uses two-wire bus independent of polarization of the wires. Simple setup procedure takes about 30 minutes (for the case of 28 users).

Intercom system for housing society - to enter the enclosed area of the housing estate we use the panel on the left; to come into a building we call the key on one of the three panels on the right.

Field measurements of WLAN networks. To assess the possibility of connecting new subscriber to the network we often need to perform a test. Well prepared testing procedure allows to select optimum equipment/device and find out whether the real throughput will satisfy customer's needs. It will also shorten the time of installation work. For such purposes we may recommend wireless PCMCIA card Ubiquiti SRC N2696 equipped with MMCX antenna connector. The card can operate in two frequency bands: 2.4 GHz and 5 GHz. The employed Atheros 5004 chipset cooperates with NetStumbler . The antenna connector allows connection of an external antenna (with E83260 connector).The included CD-ROM provides software package that enables the user to get detailed information on:

• the exact frequency of operation,
• transmission and download speeds,
• advanced statistics of sent and received packets.

Direct connection to telephone line and link sharing. Sharing of internet connection provided by xDSL technology (e.g. Neostrada in Poland) is a very popular way of connecting several computers to the Web at home. We may use:

• ADSL router (Annex A) TD-8840 N2905 or TD-W8910G N2901 - directly connected to phone line (RJ-11 connector),
• if we have ISDN line we have to use the router TD-8840B N2906 (Annex B),
• choosing TD-W8910G N2901, we have possibility of connecting the computers both with cable and wirelessly. For a laptop we use WLAN PCMCIA card TL-WN510G N2930 or wireless USB adapter TL-WN321G N2920, and for desktop PC - TL-WN551G N2970.

There are also available new 108 Mbps devices:

• ADSL router integrated with Access Point TD-W8920G N2903
• WLAN USB adapter TL-WN620G N2923
• WLAN PCMCIA adapter TL-WN610G N2933
• WLAN PCI adapter TL-WN651G N2973

Solution for sharing xDSL service

Kazakhstan. The Heavenly Mountains are called Tien-Szan in Chinese. The local name of the hill on which the tower stands is Kok Tyube. It is near Almata city (till the nineties of the 20th century - Alma-Ata).

Engagingly about Antennas - VI Summer 2007 Dipol Competition - the first works.

Architecture of Cairo - Barbara Sieja