February 19, 2007

HDTV in mobile phone - latest news from Barcelona. During 3GSM WorldCongress 2007 in Barcelona (Feb. 15-17) Texas Instruments has presented videoprocessor for cellular applications, supporting HDTV 720p standard and 3Dgraphics. TI promises to start production at the beginning of 2008.
Although watching HDTV broadcasts on the screen of a mobile seems to bean extravagance, the idea of developing such processor means that mobile TVcomes up to the same level as stationary reception. In practice, it will allowto receive HDTV programs via mobile phone to display them on any suitable screen(TV projector, LCD/plasma panel).
The 3GSM congress in Barcelona attracted 1300 exhibitors and 55 000 visitors. It means an exceptional success of organizers and big appealof 3GSM technology. For the next years it is planned dynamic growth of cellularnetworks, connected with implementation of HSDPA technology (broadband datatransmission up to theoretical throughput 14.4 Mbps).
Such broadband transmission will enable the users to utilize evenadvanced multimedia, thus at the congress it could be seen a crop of potentialapplications dedicated for this purpose.
Microsoft showed OS Windows Mobile 6 for mobile devices from smartphonecategory.
Alcatel presented conception of mobile TV based on dual system - thesame mobile can be used for reception TV programs from dedicated TVtransmitters, as well as for getting video data transmitted as streams via thecellular operator.
OmniVision introduced a mini-chip (1/10 inch) for cameras to be built inmobiles. It is based on CMOS technology and allows registration of 30 fps at VGAresolution. The whole camera module has been reduced to dimensions 4.5x4.5x3.7mm.
Fujitsu Siemens demonstrated a laptop equipped with wireless adaptorutilizing HSUPA technology. HSUPA offers much higher uplink speeds thanmentioned HSDPA - up to 5.8 Mbps.

In the near future quick growth of cellular networks will be based on implementation of HSDPA (broadband data transmission up to 14.4 Mbps).

Before the signal reaches sat receiver. MPEG-2 stream is composed of packets. Before sending, the packets containing 188 bytes (187 bytes of data + 1 synchronizing byte) are processed to obtain best possible transmission parameters.
The first stage is randomization (procedure of spectrum spreading). The process disintegrates long sequences of 0's and 1's, because such strings would be unfavorable for transmission quality.
Then each packet is being coded with the use of redundancy code. Such error correction code protects the signal against disturbances during transmission. It enables to regenerate the signal in the receiver even when some errors occur. The whole procedure is based on algorithms enabling reconstruction of the signal.
The next stage is interleaving of packets in order to eliminate possibility of longer distortions of images - due to changing the order of the packets possible distortions do not accumulate, and short disturbances may even not be noticed.
The last phase of signal processing before modulation is spectrum shaping with a raised-cosine digital filter.
So prepared signal modulates carrier wave, e.g. with quadrature phase-shift keying (QPSK). With four phases, QPSK can encode two-bit words, i.e. 00,01,10,11, that make "symbols".
Finally, the signal is shifted to e.g. Ku Band (uplink: 14-18.1 GHz). The satellite changes the band to downlink band 10.7-12.75 GHz and transmits the signal to desired region of the world. The signal received with satellite dish is directly converted in LNB into intermediate frequency (sat IF: 950-2150 MHz), which allows further transmission to the receiver via coaxial cable, without substantial loss of the signal.
The receiver performs reverse operations to regenerate the original signal.

Basic signal parameters:

• Redundancy level - Forward Error Correction (FEC): 1/2, 3/4, 2/6, 2/3, 5/6, 7/8. It shows how many additional bits are used for correction of transmitted data. For FEC = 3/4, three of every four bits carry information, while the fourth is used for correction. Lowest ratio means larger error-correction margin.
• Symbol Rate (SR) - number of words (symbols) transmitted per one second (in the case of QPSK - two-bit pairs).

Terra multiswitches - installation with 144 outlets. Multiswitches MSR-5xx/MSV-5xx allow building extensive and asymmetrical SMATV systems for reception programs from one satellite position.   There is possibility of putting some more equipment when needed. The transistors used in the multiswitches are resistant to overdriving, so the input levels of terrestrial TV signals may exceed even 90dB. Due to flat frequency characteristic, the multiswitches do not change the original distribution of the channels from the transponder.

Installation with 144 outlets, based on Terra multiswitches.

Time of recording. One of most frequently asked questions on parameters of digital video recorders is that about maximum time of registration. There is no one answer, it depends on many factors, such as disc capacity, speed and parameters of recording, and frequency of events triggering recording (i.e. frequency of image change).
For popular 16-channel DVR AVC777 M8509 some typical cases are presented in the table:

For basic quality, say in a system comprising 18 cameras, at recording speed 18 fps (1 fps for each camera) and with 500 GB disc space, it will be even 13 days. Such mode is sufficient in case of parking lots, warehouses, yards etc.
Digital Video Recorders

Day/Night cameras. Systems that are used for identification of people and objects during the day and night require employing day/night cameras.
In professional installations one has to use cameras with mechanically switching IR filter, e.g. SN-587C/A/10 SWD M11205, as only this kind of cameras ensures proper reproduction of colors. The applications include systems for identification of vehicles, also being in motion, or other moving objects.
Cheaper models without IR filter distort colors, which makes impossible proper verification of objects.

Day/night cameras with mechanically switching IR filter SN-587C/A/10 SWD M11205.

Pixord and Milestone. As part of promotion of professional solutions concerning both equipment and software, we add managing software from Milestone for each camera Pixord P400, codes K1131 or K1132, full version supporting the camera. This way the user can take advantage of free software without time limitation. In case of expanding the system, when buying license for more advanced versions of the software, the user will not have to learn the operation from scratch, being well familiarized with it.
Pixord cameras.

New panel antennas. There have been introduced functional improvements to popular antennas ATK-P4/5.5 A73901 and ATK-P8/5.5 A73902. Now they allow adjustment of tilt angle.
Newly released on the market models A739015 and A739025 are equipped with cable (0.7m long) terminated with SMA R/P connector. These antennas are especially recommended when the Access Point is mounted outdoor, in hermetic box on the same mast.

 
Antennas with cable Tri-LAN 240 (0.7m): A739015 and A739025

Mutual interference from neighboring WLANs. Growing number of users of equipment working in 2.4 GHz band means that probability of interference among many devices operating at the same channel is also increasing.
For radio transmissions there may be distinguished two ranges:
- usable range (or service area) enabling stable operation
- interference range showing maximal distance of influencing other systems.

Mutual interference among base stations. Station B disturbs stations A and C,
stations E and D interfere with each other.

An antidote against the phenomenon is taking the next steps:

• change of the channel,

• change to orthogonal polarization,

• use of directional antennas,

• change of working band.

Sat Krak 2007. This year's satellite and multimedia trade fair Sat Krak 2007 will be held from 18-20 October 2007. During the exhibition producers from all over the world will present equipment for reception of satellite and terrestrial TV broadcasts. What's more, the expo will also be the place of meeting of satellite operators, TV broadcasters, Internet and WLAN providers, and other companies that are connected with the fields.

February 12, 2007

Global or provincial - CeBIT before reform. From 15-21 March there will be held in Hanover this year's edition of world's largesttrade fair showcasing digital IT and telecommunications solutions for home andwork environments - CeBIT. The trade fair is expected to gather about 6000exhibitors and over 400 000 visitors.
Each year the organizers choose country or region of the world  thatbecomes a special guest, promoted during the fair. This year it will be Russia,represented by  150 companies (in last year's edition - 80).
Unfortunately, a crisis of European exhibitions affected CeBIT as well.The sign is absence of such captains of industry like Motorola, Nokia, BenQ, andthe fact that the total number of exhibitors will be reduced by 10% compared tolast year.
The organizers cannot forget the old good times of internet boom when thenumber of exhibitors was approaching 8000 and Intel used to present its newestprocessors here.
Competition of Asian and American fairs and decreasing production andconsumption potential of Europeans in comparison to "the rest of the world" are the main reasons of the lower interest in showing in this region.
Companies are also complaining about high exhibition costs and festivalcharacter of the event (growing number of stands with computer games), and vastmajority of non-professionals - which requires a large body of staff.
As part of a reform, from next year the fair will be one day shorter.There will be separate days for business customers and only two open days forall visitors.
Report from CeBIT 2006

Asian and American exhibitors do not appreciate festival character of the event.

Versatile wiring options for buildings. Flash guide showing set of installations required in any building, together with needed elements and equipment. We invite you here.

It happens that investors forget about antenna installation...

How to choose proper diplexer? The table below enables comparison of the most popular antenna diplexers/multiplexers from our offer.

* DC pass for powering preamplifiers
 

Antenna diplexers/multiplexers with DC pass allow powering preamplifiers. The default state is  "without amplifiers". In case of installing amplifier(s) it is needed to set/cut adequate jumper(s).

Use of coax from multiswitch installation for sending terrestrial signals. With such an installation there is possibility of utilizing one of the cables connected with Quatro LNB. There are needed two  satellite combiners DC-009. One of them combines, the second separates the SAT and TV signals. 

Better monitoring quality of compact cameras. Growing popularity of compact cameras in common applications is the result of low price, simple installation, possibility of working at night. In the case of outdoor operation, however, the frequent problem is fogged-up lens or pane. Low temperature in the night and quick rise in temperature after sunrise or fast drop in the evening are the reasons of the fogging effect. So, buying a compact camera for outdoor applications it is worth to pay attention whether that model is equipped with built-in heater.
 

N-cam 115 M11234 has been equipped with heater that eliminates the problem mentioned above.

Tester CCTV TOMEK-8. Universal CCTV tester - Tomek 8 M2508 - provides invaluable service while starting up new CCTV systems as well as maintaining and repairing them. The tester has eight functions:

• Measurement of power voltage.
• Indication of improper polarity of supplying voltage.
• Measurement of ripples.  

A typical sign of ripples are broad horizontal strips on the screen (the picture can be enlarged).
The ripples come from the mains (usually as the second harmonic, i.e. 100 Hz in Europe).
Regulated power supplies normally have very low level of ripples, which is negligible.
The ripples will be significant in case of damaged filtering capacitor or overloading the supplier.

• Measurement of video signal.
• PAL generator. 
• Control of lens ZOOM.
• Control of lens FOCUS.
• Opening and closing diaphragm in lens with automatic aperture control.  

The diagram shows example testing of video splitter. The checked device is marked with the circle. Setting the tester into measurement of video signal (p-p), we first measure the input level (A point). Then we change the point to the output (point B) and compare the two values.
They should be practically the same.
This simple method enables the installer to quickly check the splitter.
Similar tests can be performed with other devices like video separators, video switches, QUADs etc.

Economical solution for offices - Pixord cameras. Implementation of modern monitoring system in an office does not have to be expensive. There are available dedicated devices that support such economical applications. An example is IP camera from Pixord - K1130. The system based on the cameras can use up to 16 devices and will be supported by free management software.
Local registration of images on SD card, triggered by motion detection, enables full control over monitored area. Built-in microphone may be used for voice recording. Nice look and small dimensions make the cameras an interesting complement to the office environment.

CCTV system based on Pixord cameras K1130 features: triggered by motion detection registration of images and sound on SD cards (slots in cameras), alarm and continuous recording on network computer, remote viewing via the internet, wireless transmission of images and sound.

Arrangement of channels in 2 .4 GHz band. From 13 channels there are only three that do not overlap, e.g. 1, 6, 11, or 2,7,12 or 3,8,13. Even better isolation will ensure the trio 1,7,13.

Access Point WAP-354NB N2515 with WISP function. This Access Point features 5-port switch and dual radio system working in 2.4 and 5 GHz bands.
Modes of work: Access Point, Access Point Client, WDS, Wireless Routing Client (WISP), Repeater. Simple configuration will not cause problems even for novices.
For many users the most useful mode is WISP (Wireless Internet Service Provider) which allows reception of WiFi signal and sharing it among integrated LAN ports (the device works as client station, but it is still active routing between wireless link and the LAN ports). Possibility of adjustment of ACK parameter and the RSSI indication make the device useful even at distant client stations, both in 2.4 and 5 GHz networks.
To sum up, with this Access Point one may create local network having wireless access to the Internet. It is a cheap solution for home or business.

The Access Point features 5-port switch and dual radio system working in 2 .4 and 5 GHz bands.

February 5, 2007

The English set trends – IIPSEC 2007. The most significant globalsecurity exhibition (IFSEC) is held inBirmingham, while in nearby Coventry, every year in January, the producers,installers and users of IP-based monitoring systems have their meetings at IIPSEC.
This year's IIPSEC exhibition and conference took place between 23-25January. About 100 companies presented IP CCTV equipment, there were held dozensof conferences and lectures. For the first time, one of the organizers of thecourses for IP CCTV installers was Cisco Systems, Inc. The world's giant ofnetwork technology had spotted the potential of CCTV market.
The newest trend that we have noticed in Coventry is wider offer ofmegapixel cameras. Cameras currently used in surveillance systems are more oftencharacterized by increased resolution at the expense of lower number of framesper second. They satisfy rising demand for detailed images rather than theircontinuity.
There is seen broader and broader choice of IP CCTV software. Theleader, Milestone, is followed by many competitors - the software solutions havebeen presented much more widely than last year.
IP CCTV monitoring systems or their elements are more often based onwireless networks, due to much easier installation and lower costs. Meshnetworks are especially useful for city systems.

Megapixel IP camera from Lumener showed in Coventry, ensuring images built of 10 million pixels
 at 5 fps or 2 .5 million at 20 fps. The employed image sensor has 43.3mm diagonal.

Surge protection of receivers. For all who want to avoid damage, and mostly the situation of  being under constraint of buying a new SAT receiver, multiswitch, TV set or stereo after thunder storm, we offer small and cheap device Signal R48602. The protector operates over full range of terrestrial and satellite TV. It can take over current up to 4500A, with rise time 8us and duration time up to 20us.
Notice: In the diagram below it is used combiner passing DC power to AM-316 amplifier. Most of SAT receivers, even in standby mode, give at their input DC voltage that is regulated at the output of the TV combiner R85312 to 12V level.

Example of installation protected with the devices R48602

How to make community antenna installation ready for change to cable TV system? At the stage of designing multi-family  buildings it is worth to take into consideration possibility of future adaptation of antenna installation to cable TV system.
Such conception does not increase costs at the phase of construction and allows easy modernization of the wiring through connection of cable TV signal. Many or even most of cable TV suppliers offer a whole range of services, usually analog and digital TV, telephone service, internet access.
The design process is similar to the case of community antenna installation but there should be added several important supplements:

• distribution structure has to be based on taps that ensure separation between outlets
• every apartment has to be connected via separate cable (possibility of grouping services and data transmission)
• there should be planned space (box) for building amplifier in the basement - it will replace channel amplifiers used in community installation
• it is worthwhile to lead 2 cables from the basement - it facilitates implementation of service packages and lowers the cost (only two filters will be needed for the commonest solution with basic and premium packages)
• in case of high buildings it is recommended to make subdivision into two subnetworks.

The cabling should be made with quality coaxial cable TRISET-113 E1015, employing F-connectors crimped on the cable, e.g. E80271.

Diagram of cabling for ten-story building that facilities introduction of cable TV.

Modernization of community TV installation - IF/IF conversion.  Newly built buildings should be equipped with antenna installation based on multiswitches - both one-family homes and multi-family houses.
In the case of older buildings having installation with pass-through connections there is possibility of using IF/IF conversion, and distributing satellite broadcast to every apartment, on condition that the coaxial cable ensures proper quality (is capable of working up to 2150 MHz)
The idea of the conversion consists in selecting any transponders from any satellites and transposition of their frequencies to planned area within SAT IF range (900-2150MHz). The subscriber outlets are supplied with satellite "destination" signals - there is no need to switch converters. This solution enables the provider to distribute to each outlet over 200 satellite programs.
The proposed installation is based on splitters and taps. There may be used loopthrough satellite outlets in case of multiple outputs in one apartment (for several receivers).

Diagram of building installation employing IF/IF converters. From one satellite installation one may distribute signal containing over 200 programs via comparatively low-cost cabling.

The last Thursday of carnival of princess Maria Krystyna von Habsburg - CCTV in bakery in Zywiec. The professional journal "Bakery Review" has published an article on support of running bakeries with modern telecommunications and IT systems. Here is the fragment about CCTV solutions:
"To date, CCTV systems have been used mainly for security reasons. We have made step forward. We use them for sustained improvement of customer service. From the headquarters we control displaying of products and quality of staff work - their commitment, diligence, meticulousness. There is no chance for empty shelves. The system is also utilized by our workers. Working in network of small bakeshops they are able to react quickly to the demand for specific assortment in the retail chain.
On the other hand, the customers shopping in the chain of shops can view live images from the bakeshops. On the shop screens we may present images from a dozen or so cameras. Before different holidays, or traditionally on the last Thursday of carnival, the customers are really interested in the magic of making pastry, rising it, and then  frying doughnuts and cenci, as well as in the true story of any cake. This marketing action that shows perfect production processes encourages customers to buy these delicious products. They will not rather buy "cheap" confectionery that may be manufactured under unknown conditions. We have also installed monitors that display presentations of our assortment, new products etc."
New technologies help to conserve traditional prescriptions and high quality. Princess Maria Krystyna von Habsburg is one of the lovers of frying doughnuts from Galuszka bakeshop in Zywiec. We are curious about which kinds she prefers - the shop sells 33 kinds of the doughnuts!

CCTV system in bakery in Zywiec based on equipment from Dipol and WiMAX network
deployed by SferaNET.

How to utilize an existing LAN cabling for transmitting video signal? LAN signal transmission via twisted pair cable uses only 2 pairs (4 wires), the remaining 2 are left intact. Thus it is possible to utilize them and transmit 2 video signals differentially, without affecting the computer network.
It can be accomplished with the aid of Quad-to-Quad Switch LTR-2 M1703 connecting a computer network with the transformer TR4/4 M1667. The device can be used in various systems.

The use of an existing computer network for video signal transmission.

IP-CCTV - an ideal solution for ports and shipyards. Due to sharpening of regulations concerning security of vessels and port infrastructure (ISPS code), Ølen port in Norway has taken steps to improve and extend monitoring system. To limit the costs of implementation of the new system it has been decided not to use expensive solution with coaxial cables, but utilize existing Ethernet cabling. As the operating computer network has guarantied internet access, surveillance system based on IP network ensures improved flexibility. The existing cameras have been connected to videoservers ACTi K2112 which convert analog signals to digital format and  send them via IP network. In the new locations there have been installed stationary cameras K1114 and high speed cameras K1215. Thanks to IP-based system, it has been added possibility of remote control over all cameras from many monitoring stations. Additional advantage is option of viewing images from all points via the Internet.
Ports and shipyards often use IP surveillance systems by reason of lower costs of implementation and easier installation of cameras in existing and new locations.

 
Illustrations from www.acti.com

Planex GW-AP54SP-P as Wireless Internet Service Providers (WISP). In this mode the role of WAN interface is performed by wireless port. It means that  having one IP address assigned by service provider we may share it among a number of computers (with router , NAT, Virtual Server, DHCP, firewall functions). There is also possibility of changing MAC address.

Yagi or panel antennas - which are better? Popularity of Yagi antennas is the effect of low price and good parameters that are optimal for client stations. The next advantage is easy assembling, as the result of quite wide half-power angle. That's why direction adjustment of Yagi antenna is not so critical like with parabolic or offset antennas. On the other hand their directivity is sufficient for suppressing unwanted signals coming from different directions, being simply interference.
Panel antennas, similarly to Yagi-Uda antennas, are designed for use at client stations, but sometimes are employed at base stations, too - working with APs. Their gains are comparable with Yagi antennas. However, there are serious differences. Firstly, panel antennas have half of the beamwidth of Yagi ones, what means they have higher directivity. Secondly, well designed panel antenna should be "resistant" to orthogonal signals, meaning high suppression of signals having the other polarization. The ATK-P4 A7127 panel antenna features cross polarization rejection at minimum level of 29 dB.

January 29, 2007

Television in the Royal Castle in Niepolomice. The Royal Castle in Niepolomicenear Krakow had been built in XIV century for Casimir the Great. It was hisfavorite haunt, as well as of the successor Wladyslaw Jagiello. The castle sawmeetings of kings with the royal council, as well as big-game hunting trips withparticipation of foreign dignitaries. Up to the end of XVIII century the castlewas owned by aristocratic families: Czurylo, Branicki, Lubomirski.
On 12 January 2007 there was opened a luxury hotelthere. It is the only hotel in Poland that is located in Royal Castle. In 24apartments and rooms it is place for 54 hotel guests hosted like kings. Everyroom has been equipped with LCD television, allowing to watch a variety of TVchannels and the course of conferences taking place in the Conference Center.
For the reason of high quality requirements, the installer of thesystem, ZSK Krakow, has chosen solution based on channel amplifiers. The signals fromterrestrial antennas and satellite headend have been led to set of channelamplifiers - ZG series from Alcad. High output level guarantied by the amplifiers, quality coaxial cable Triset-113 E1015 and well-tried Signal passive equipment - all the elementspermit direct distribution of the signals (without use of additionalamplifiers), despite some cable routes exceeding 100m. The TV network enablesthe guests to watch conferences transmitted by cameras placed in the ConferenceCenter, with the use of MT-30A R871731modulator.

The courtyard of the Royal Castle in  Niepo³omice.

Modern antenna installation in multi-family building. This installation enables each resident to receive via his antenna outlets any terrestrial or satellite programs.
The multiswitches of the MS-952/951 series (for two converters) are suitable for building extensive community SMATV installations with a hundred or more outlets. However, large systems require employing amplifiers. There may be used amplifiers from Terra, or from the Signal family -  R694490 for single converters, and R694491 for double converters. The amplifiers ensure adjustment of parameters both within terrestrial and satellite band.

Burglary in Krakow. We see a rise in popularity of residential monitoring, where images from the cameras installed in the building are available on televisions of the occupants, at the same time being recorded on a DVR.
Usefulness of such a system has been appreciated by the occupants of the tenement in Szewska Street in Krakow. Breaking into one apartment, the burglar did not pay attention to simple monitoring system based on DVR and three CCTV cameras.

Images from the camera at the entrance and two cameras placed in the staircase allowed analysis
of the people coming in and out of the building on the day of burglary. Good quality
of records helped the police to catch the perpetrator.

Diagram of simple and stable CCTV system for monitoring a house/building/tenement.

Power for cameras. Most problems with wrong operation of cameras are caused by improper power supply.
The reason of the problems is usually unsuitable power supply adapter, not guarantying sufficient output current. It should be remembered that a standard indoor camera needs ca 250 mA, whereas outdoor version with a heater will need ca 1000 mA. For local power supply there should be chosen supplier with adequate capacity from among M1810, M1812, M1824.
Remote powering of devices introduces additional complication - voltage loss in the wires. In the case of DC 12 V and longer wires with small diameter the loss may be excessive, beyond the tolerance of the camera. It is assumed that cameras tolerate  +/- 10 % change of rated supplying voltage (10.8 V - 13.2 V). Outside the limits there is a risk of deterioration of image quality, inoperability, or even damaging.
The problems can be overcome by using proper power supplies:

• power supplies with specified current capacity, ensuring adjustment of output voltage. They are used in situations where long cables are indispensable. These are e.g. M18285, M18287, M18289.
• "power systems" - sets of devices based on power supplies with much higher output voltages and local stabilizers. They are recommended for extensive CCTV systems, the examples are M1830 and M1831.

Camera control switches. Cameras are equipped with a number of switches and adjustments enabling adaptation of picture parameters to the real environment. Here are typical adjustments provided by color CCTV camera, and basic connectors:

• AWB (Auto White Balance) - correction of the image according to predominant kind of light: ON (artificial light) / OFF (natural light).
• AGC (Automatic Gain Control) - stabilizes output signal level and improves S/N ratio; image is more clear however less natural. Switching off this function will effect in more natural image but also more noises.
• EE/AI (Electronic Shutter) - in the EE mode electronic shutter ensures adaptation of exposition time to current lighting conditions. In the AI mode the shutter is set to constant time (e.g. 1/60s), and the exposition level is controlled by the lens with Auto Iris.
• BLC (Back Light Compensation) - function allowing to correct quality of overexposed image.
• DC/VIDEO - switch for selection of AI control system.
• LEVEL – potentiometer for setting demanded level of brightness (the adjustment applies only to DC lenses).
• VIDEO OUT - video output connector (1Vp-p, 75 ohm).
• 12V DC IN - power input socket.

Sharp edges of objects, true colors, sensitivity 0.8 lx and resolution of 420 TVL - all that due to employed SONY Super HAD image sensor, together with a variety of control options - locate the camera M1128 among devices above average standard. All for a very attractive price.

Client / server software for IP CCTV systems. Client / server software architecture is an unsymmetrical organization of software solutions that  separates some functions of the system to make it more versatile and prepared for easy modification of each part.
The idea consists in establishing a certain set of programs that support another group of applications. One server usually supports many clients, it is also possible that one client makes use of services provided by a number of servers.
Such an architecture forms the basis for the new server software pack ACTi NVR ( Network Video Recorder) cooperating with the well known Streaming Activator client pack. NVR has been designed for servers controlled by Windows Storage Server 2003.
User-friendly interface enables the user to easily configure the server as network video recorder. Any of 64 channels can support a camera or ACTi videoserver. For each camera it is possible to set  individual recording schedule, motion detection parameters, user accounts and authorization rules, disc location (for video recording). There is also possibility of monitoring disc space of the server, searching and viewing of recorded material. Change of configuration and viewing of records is possible both within local network and via the Internet. Since internet browser allows for viewing one camera only, it is convenient to employ Streaming Activator, which, as the client, offers alternative of simultaneous viewing of images from all cameras. Having such powerful and versatile tools one is able to build and run large surveillance networks capable of effective processing and recording of large amount of information generated by video systems. NVR and Streaming Activator (the version up to 16 channels) are free of charge.
IP CCTV equipment from ACTi.

Remote access to CCTV system. LAN or WLAN may be used for transmission of video streams containing data on protected areas. Many DVRs allow access to video data via the network (e.g. M85040, M8534, M8537, M85075, M85077).
The diagram below shows application of TP-Link device  - TL-WR542G N2950, for building such network. TL-WR542G provides functionality of Access Point (working at 2.4 GHz), router and 4-port switch. It enables the user to share xDSL connection among 4 LAN ports. They may be redirected the way that will allow to access the connected DVR from any place in the world, at the WAN address of the router. The device also supports DDNS service, which is important in the case of dynamic IP address. There is possibility of creating internal network (behind the router) by equipping desktop PCs with the cards TP-Link TL-WN551G N2970. To use laptops, notebooks, etc. they should be provided with the cards PCMCIA TP-Link TL-510G N2930. All the mentioned network adapters as well as the device TL-WR542G support eXtended Range technology. This solution ensures higher network capacity than IEEE 802.11g itself.

Influence of RF cable on WLAN range. Exchange of the cable for another one having lower attenuation gives the means to increase the power applied to the antenna, thus the radiated power and range. As an example, swap of  10m of H155 cable for the same length of H1000 increases two times radiated power, which turns into extension of range by 20 - 40 %. The best cable within the H-155 class is Tri-Lan 240 E1171 (over 20 % lower attenuation than in the case of H-155).

The example and the table have been prepared for the model of free space, on the condition
of undisturbed first Fresnel zone. The conclusion - influence of the kind of cable used is significant
for distances of 10m or more.

January 22, 2007

CCDP – new tendencies in video monitoring. CCTV (Closed Circuit TeleVision) is the basic method of monitoring any kind of space. The main shortageof CCTV surveillance is comparatively low resolution of images. Standard PAL camera provides image containing ca 400,000 pixels. The resolutions thatare commonly available in digital still cameras are 10 times better (taking intoconsideration the number of pixels). Such resolutions enable enlarging the wholepicture or its interesting fragments, preserving satisfactory distinction ofdetails.
It has been proofed that in many cases (e.g. registration of personscoming into a building, shop etc.) speed of recording is not so important andmay be significantly reduced in comparison to standard 25 complete frames persecond in the PAL system. Thus the idea of CCDP (Closed Circuit Digital Photography)is finding a growing number of applications. CCDP permits registration of highquality material at slower rate, e.g. one shot per second. Having highresolution pictures the user and the police can utilize this advantage forproper identification and providing the body of evidence that is often superiorto regular CCTV recordings. More on CCDPhere.

Low resolution of the image did not enable the police to identify offenders
who robbed this computer shop.

Installation of HD satellite receiver with PVR – choice of switches and multiswitches. In our lab we have tested dishes, switches and multiswitches for interoperability with new generation of digital satellite receivers equipped with personal video recorders, basing on the "nbox" receiver prepared for Polish "n" HD platform. The newest available software (accessible via satellite) generates both ToneBurst and DiSEqC signals, so we have examined compatibility of some popular products that support those standards.
We checked the switches Viper R85250 and Golden Interstar R852506, which worked perfectly with the receiver.
More critical issue is choice of multiswitches. Due to standard control signal there is no problem with switching (we tested three different multiswitches). But we noticed differences in spectrum of the RF signals after going through the electronics of the multiswitches. The problem concerns any similar platform, and may influence quality of signals within larger installations (too big differences in signal levels). The lowest level of spectrum distortions we got for the multiswitch Terra MS-952 R70952.
The measurements were performed with use of HP 8593 E spectrum analyzer.

Spectrum of the signal after coming through the multiswitch Terra MS-952 R70952 - in the middle there is the transponder of "n" platform - the signal is evenly distributed within whole frequency band.

Spectrum of the signal after going through the "X" multiswitch - it is seen larger attenuation
of the signal at higher frequencies. It may cause problems in the case of larger installations.

How to care for coaxial cable to save its parameters - return loss. One of the key parameters having strong impact on overall cable quality is return loss which says how much of the applied power returns to the source of energy.
Deterioration in matching may be caused by the installer who changes geometry of coaxial cable when making the installation. Typical situations include treading on the cable, using force to draw it in, stuffing and bending cables in the boxes, sharp bending of the cable, or unprofessional mounting on the walls. The last case concerns using various clips, often applied by mechanical tools. When the clips are too tight, they locally change geometry of the coax. Additionally, they are often used in excess, to keep even intervals for esthetic reasons. Correct fixing of the cable requires using not many clips on straight sections and more at curves. It should be preferred manual mounting, or use of minimal settings in case of employing tools. And the clips should be placed according to the above recommendation, at uneven intervals - to keep the original return loss of the cable.

Guidelines for cable distributors from the manufacturer of  the coax Triset - 113 include ban on putting rolls of the cable one on another. To protect the cable against possible deformation the producer places the rolls in cardboard boxes that are indispensable during the whole distribution process.

CCTV system in one-family house. Properly designed antenna cabling enables easy expansion of applications, e.g. combining signals from CCTV cameras.

The diagram shows installation distributing signals from two satellites and terrestrial antennas to four outlets. Two cameras connected to modulators allow viewing monitored areas on two freely chosen channels.

The monitoring system may be provided with a digital video recorder. DVR equipped with motion detection function will enable recording of the selected events when motion is detected.
The cameras suitable for these applications are compact color cameras with IR illuminators.
Observation of the surroundings requires to employ outdoor cameras that usually cover a distance of 10-20 meters. Very good solution is use of the camera n-cam 115 M11234 or n-cam 220 M11235, both equipped with SONY CCD image sensors, the latter - with SuperHAD version, characterized by increased sensitivity. In both models the built-in IR illuminators provide effective lighting up to 20-25 m.

Surge protection of video lines in CCTV installations. On of the most common reasons of a DVR failure is electrical surge in the video line. The statistics show that about 25 percent of damages of electronic equipment are caused by overvoltages induced out of electromagnetic field during close lightning strikes. The Video Line Overvoltage Limiter (surge protector) OPV-1 M1701 (for one camera) or OPV-4 M17014 (for 4 cameras) effectively protect video line/s carrying away the stroke current to the ground. This way the excessive voltage is strongly limited and does not harm connected video equipment. The devices do not affect video signal quality and no power supplying is required.
Ultra-high-speed switching diodes of large admission power have been applied. In case of appearing a voltage over 2.4V between the signal line and the ground, the diodes will short close the circuit with tremendous speed, eliminating the overvoltage and securing camera/s or other equipment like DVR, video capture card etc.

This connection of OPV-4 M17014 allows to secure monitors or other equipment (e.g. DVRs).

NVR - video stream recorder of images from IP cameras. The software pack NVR from ACTi gives any PC functionality of network video recorder. Using a local or remote host we may get access to the NVR server and manage the whole IP CCTV system. NVR enables active control of up to 23 discs of the server and monitoring the storage capacity of the system. It supports up to 64 cameras at D1 resolution and 30 fps. The software ensures remote access to records and viewing them via an internet browser or included Streaming Activator program. NVR provides development of ACTi system by client-server architecture, enabling partition of viewing functions (Streaming Activator) and recording facilities (NVR), in order to improve flexibility of the whole system.
IP CCTV equipment from ACTi

A screenshot from NVR

Video capture system - the hybrid NUUO solution. The video capture card NUUO K2320 enables building hybrid systems, i.e. combining in one CCTV installation analog and IP devices. The NUUO software pack supports most of devices available on the market, among others: ACTi, AXIS, SONY, PIXORD, BOSCH.
In case of occurrences like triggering motion detection, detection of new object or lack of previously existing one, loss of sharpness, change of camera position - the program can execute one of preprogrammed  actions. They include: on-screen information, alarm sound, e-mail notification, phone notification, PTZ procedure, triggering of external alarm.
Program comprises all commonly used functions, e.g. scheduling of recording tasks, setting of  the number of simultaneously viewed images. An interesting option is possibility of sharpening  the previously recorded image.

The concept of hybrid CCTV system.

Choice of equipment in order to meet EIRP compliance. Are we allowed to use antenna with extremely high gain, not breaking the law? It should be stressed that there are no rules on limiting the gain. So, why one person obeys regulations having antenna with 15 dBi gain, while the another breaks them using a 10 dBi antenna? And why some manufacturers of RF equipment state in the compliance certificate that it is required a 15 dBi antenna, when others anticipate 10 dBi gain?
The answer to the questions follows directly from regulations concerning maximum level of radiated power EIRP. In many countries, without special license, the maximum EIRP = 100 mW, i.e. 20 dBm in 2.4 GHz band and 1 W (30 dBm) in 5.47 - 5.725 GHz. The same level of EIRP may be accomplished by many mans:

EIRP_[dB] = transmitter output power _[dBm] – (loss of connectors _[dB] + loss of cable _[dB]) + ant. gain _[dBi] <= 20 dBm (for 2.4 GHz)

EIRP_[dB] = transmitter output power _[dBm] – (loss of connectors _[dB] + loss of cable _[dB]) + ant. gain _[dBi] <= 30 dBm (for 5 GHz)

It is now clear that the borderline value of EIRP may be reached by adequate selection of transmitter's output power, kind and length of the cable, and gain of antenna used.
It's worth stressing that it is much more advantageous to use lower power transmitter and the antenna with higher gain than the other way round. Why? From the link balance we see that desired radiated power level can be achieved in any way, however the base station isn't only a transmitter, but also a receiver, and then, when it receives signal from a client, no matter the power has been transmitted, only sensitivity of the receiver and gain of the antenna is important. So the gain of antenna is important both during transmitting and during receiving.
The gains of client stations should also be selected carefully. The client who uses a high gain antenna close to the base station, although he receives strong signal, he may also interfere other, even distant networks during transmitting.  Besides that he will "see" those networks and what it implies, they will cause additional noise (the higher noise the larger number of errors and lower transmission speed), or he will even share the transmission medium with them - which will also effect in lower speed. On the other hand, client stations with lower, optimal for that distance gain will only see the base station and won't cause such problems.

January 15, 2007

"One World, one disc" – will it be true? - CES 2007 Las Vegas.The 2007 International CES, the largest tradeshow for consumer electronics,closed last week.
For four days over 140.000 visitors from all over the world watched thenewest products presented by 2700 exhibitors.
Twelve products have been awarded, here is a short presentation ofseveral winners.
Korean LG Electronics showed Super Multi Blue Player "reading" both Blu-ray and HD DVD discs. Just this hybridsolution won "Best in Show" title. Will such a concept be a pushtowards popularity of the new, advanced formats? The companies that support HD DVDclaim that will sell 2.5 millions discs by the end of this year, their Blu-raycompetitors boast of four times higher forecast.
Verizon Wireless presented TV technology for mobile phones - "V Cast Mobile TV".The service should be available in March, and at the start will offer choice ofeight channels (including CBS, NBC, MTV, Fox, ESPN). The company promises standard TV image quality, and very goodsynchronization of picture and sound. So far, the service may be run on twomobiles  - LG VX9400 and Samsung SCH-u620.
Will the battery stay charged forever? So maintains Pennsylvania companyunveiling their  Powercast. The device will wirelessly provide powerto multiple small appliances within its reach. It means that the battery ofwireless phone, mouse, keyboard etc. won't need to be recharged at all. Justforget about it!  This invention will be commercially available by the endof 2007.
Next wireless solution is Sansa from SanDisk. This MP3 player enables the user to get connection tothe web via any hotspot and download music, pictures, or even listen to internet radio.The player will cooperate with music portals (not specified yet). Sansa isequipped with 4 GB memory and slot for SD cards. It will be launched in March.
Samsung FP-T5894W – 58-inch plasma panel with 802.11ntransmission module allowing transmission from home theater center  up to 100 m won competition for the best TV set.
We encourage you to be a CES judge - thissite presents 36 productsnominated for CES awards.
Are your opinions the same as those of American jurors? - Here are all the winners of classified categories.

The largest LCD television shown at CES was 108-inch diagonal (274cm) Sharp from Aquos family.

Not enough cables? There is possibility of connecting satellite installation with two fullband converters and set of terrestrial antennas even to one coax cable. Such layout should be based on cascade connection of satellite and terrestrial diplexers. Inside the building there will be needed satellite outlet that separates each kind of signal.

Application of the diplexer DC-09 R85300

Galvanic isolator (translation from discussion forum). Damn it, I struggle with the hum (...) I've measured 46V voltage between the cable TV outlet and case of my computer!!! The PC is connected to wall outlet with neutral grounding, of course. It's a horror! Happily the power installation is not equipped with differential protection, that would be fun ;-) In any case, I must constantly pull out antenna plug when want to have a blessed silence. Besides, I'm anxious something happens in the end...I've ordered galvanic isolator for cable TV, will it help a little?
> I had similar problem. I've just inserted such isolator at the input of cable TV and everything calmed down! :-))))). What's more, the interferences that sometimes spoiled TV picture disappeared as well. I'm happy now! By the way ...
(...) some emotional words have been skipped :-).

One of problems of large cable TV networks is generation of unwanted potential differences.
This phenomenon is the source of interferences decreasing quality of picture and sound. The remedy is application of galvanic isolators, e.g. R48605, which separate both the "hot" (core) wire and the screen of coaxial cables of external and internal (home) circuit.

Camera with Super Wide Dynamic image sensor. SWD cameras are equipped with the newest generation of image sensors, developed by American Pixim company. Each pixel of the camera makes a separate analog-to-digital converter. The imaging system ensures optimal time to sample and store the pixel information - there is eliminated both under- and over- exposition. Such cameras are ideal for work "against the light".
The camera SN-587C/A/10 SWD M11205 has found applications in many theaters. It was chosen from a selection of cameras and proofed to be the winner in such tough conditions (strong spotlights, quick changes of lighting, immense dynamic range - from total darkness to light flooding). The camera features useful NightVision function. When activated - it changes mode of work into B/W option. Good results in IR light ensures movable IR filter, allowing to take full advantage of IR sensitivity.
One picture is better than a thousand words - and it is below.

On the left - picture from the camera SN-587C/A/10 SWD M11205  with Pixim sensor, on the right - from a typical camera. The SWD camera, using Digital Pixel System (DPS), provides inclusion of A/D converter within each pixel of the image sensor, which significantly improves image quality
in scenes consisting of both bright and dark areas.

Monitors - ergonomics. Proper distance between the viewer's eyes and the monitor screen is an important factor of comfort and efficiency of  work. The drawing below shows optimal distances for some typical sizes of screens.

Day/night lenses. In outdoor CCTV applications the standard solution become day/night cameras, e.g. M11202. They also provide excellent results in situations requiring IR illumination. One should remember that regular lenses do not ensure good results with IR lighting (lack of sharpness - the same may occur when using some kinds of artificial lighting). To conserve high image quality of the cameras in "pitch black" environment (or with any kind of artificial lighting), it is advised to employ quality day/night lenses.
Day/night lenses from Jensen.
 

With natural light both kinds of lenses provide good results.

With IR or artificial lighting it can been seen distinct superiority of day/night lens.
(Materials from Jensen)

Dual stream - double video stream in IP CCTV. „Dual stream” means possibility of sending by the camera two (there is possible higher multiplication factor as well) streams of video data, characterized by different parameters. They may differ in:

• kind of compression (MPEG-4, Motion JPEG etc.),
• resolution,
• number of frames per second.

Double streaming enables diversification of image quality depending on use and importance in surveillance system. As the bandwidth of IP networks is limited, it is important to control the generated streams, especially the video ones, which even after compression require capacious transmission channels. According to system requirements, the traffic in the network may be controlled by putting constraints on the streams:

• viewing high-resolution images, recording with lower resolution (or vice versa),
• higher quality images in LAN, lower in the Internet,
• viewing of MPEG-4 images, recording of Motion JPEG stream (or vice versa).

Popular method of generating double video stream is use of different algorithms of compression. The cameras that implement this method usually employ MPEG-4 and Motion JPEG (e.g. K1131). Motion JPEG guarantees high quality image, but due to large data stream it is needed reduction of sent frames per second in the IP network. MPEG-4 offers a little bit lower quality, on the other hand ensuring smooth transmission of high resolution images without necessity of fps reduction.
In some cases there is needed diversification of streams relative to resolution. Lower resolution is adequate for mobile terminals (phone, pocket PC etc.).
Practical way of implementing double streaming is diversification of the number of transmitted frames (e.g. K1215, K1115). Even though reduction of fps number causes lack of smoothness of the video, the images still keep the original resolution. Use of double streaming will allow for live viewing of smooth high resolution video and simultaneous recording of reduced number of frames on the server. This way we can effectively limit network congestion and size of records. It is consistent with the principle observed in professional IP CCTV systems - quality and resolution of the image is more important than the number of transmitted frames per second.

MJPEG/MPEG4 IP camera Pixord P400 K1131 generating dual video stream.

eXtended Range - greater range of WLAN. "eXtended Range" technology developed by TP-LINK company allows for 2 - 3 times (802.11b) or even 4 - 9 times (802.11g) longer range of operation in comparison with similar regular devices, ensuring full compatibility with these standards.
This technology has been also utilized in the wireless PCI adapter TL-WN551G N2970 and access point TL-WR542G N2950 with built-in router and 4-port switch.

January 8, 2007

World trends in wireless network technology for 2007. In the current yearwe will probably see a number of interesting events regarding wirelesstechnology. It approaches the decisive battle for dominating standard of mobilenetworks, between cellular operators implementing 3G (HSDPA) technology andtheir competitors using new WiMAX solutions for mobile applications. Americancompany Sprint plans to run, for 3 billion dollars, WiMAX system covering thewhole USA. This venture may be a watershed which will cause drop in prices as aneffect of mass production. What is more interesting, the Sprint company is theowner of 3G network made in EVDO technology, so it seems to be an internalcompetition.
Growing throughputs of cellular networks together with lower prices ofconnections/data transfers will bring into general use a new group of mobilephones, so called - smartphones. Smartphones integrate several functions:regular mobile, e-mail client, web browser, GPS terminal, as well as digital andvideo camera. The supported by Microsoft Mobile OS can also read documents(.doc, pdf).
Many interested presentations of new wireless solutions we will see thesedays. During the starting International CES (Las Vegas, Jan 8-11, 2007), Cingularcompany will introduce IMS (Internet Protocol Multimedia Subsystem) technology. Basing on HSDPA, there will berun mobile video telephony.
The next technology that will be shown to the public at the tradeshow is eCoupled- allowing for efficient wireless power distribution to mobile devices. The intelligent wireless electricalpower and data transfer is realized by means of inductive coupling.
There is also seen quick development of home wireless applications. Justafter wireless HDMI platform based on Ultra Wideband technology (UWB) has beendeveloped, it comes its competitor for home HD transmissions -  802.11nstandard.

Wireless PCI Linksys WMP300N-EU adapter N2882 using 802.11n standard ensures longer rage than UWB devices.

Where is the tower? The city was already capital of a country in 1000 B.C., and its current name may be translated as "Northern Capital".
In 1215 A.D. Mongols made incursion into it destroying many buildings. The rebuilding of the city after the ravages was run by the grandson of the invader (Genghis Khan) - Kublai Khan, who named the city Dadu (Big Capital).
The TV tower seen on the picture is seventh highest construction of such type in the world. What is the popular name of the city? The answer at the end of this issue.

Seventh highest TV tower in the world - 405 m.

How long can be sat coax linking LNB with the receiver? As is known, the main criteria of proper reception are determined by BER and S/N ratio. Analyzing relationship of the two parameters with  EIRP of the set - antenna, converter, cable, receiver - it turns out that when loss of the cable is considerably lower than gain of the converter (actual level of the received signal is not taken into consideration here), then the impact of the cable attenuation is of no importance. It is enough to ensure 20 dB surplus of LNB's gain.
Taking into consideration single converter Inverto IDLP-40SST White Tech A9825, having minimum 50 dB gain, the cable may attenuate the signal even by 30 dB. Such loss has the section of the Triset 113 E1015 cable that is a hundred meters long.
Using not so good cable, with a higher loss, e.g. YWD 75-0.59/3.7 (55dB/100m), the maximum distance is still quite long and reaches ca. 55m.

Percentage of braid coverage and shielding effectiveness of coaxial cables. Many installers, when choose the coax, pay attention to its braid. Although braid coverage is important and conditions shielding effectiveness, is not identical with it. Shielding effectiveness is a function of many factors and the only reliable indicator of immunity to external interferences.
This percentage may vary from 40% to 95% with one braid layer to 98% with two or more layers. Two materials are commonly used as shields - braided copper and aluminum foil or layer that is bound to polyester or polypropylene foil base. The foil configuration used for aluminum version provides more complete coverage. Additional improvement of shielding effectiveness can be obtained by applying next layer of foil. This way we get so called Tri-shield cable having the structure foil-braid-foil. There are also cables marked as super-shield or quad-shield, with next layer of braid. Admittedly, the improvement in this case is not so much, but the solution increases elasticity of the cable and its resistance to repeated bending.

The cable Triset 113 E1015 features screening factor >=100 dB within the 30-2400 MHz range.

Monitoring of a small shop. For observation of people, goods, cash - connected with identification purposes - there are preferred color cameras, ensuring additional possibilities of recognition due to eye's color perceiving mechanisms.
In case of poor lighting conditions there are used cameras equipped with IR illuminators, which makes possible to monitor the area even in total darkness.
Outdoor camera keeps under surveillance the shop front and entrance. Owing to the need of round-the-clock observation, there are used here cameras with IR lamps, like n-cam 220 M1127.
In more demanding situations, when one requires high quality images, there should be used color day/night cameras, e.g. SN-486C M11202, in cooperation with special lenses equipped with automatic iris e.g. M2136. Application of these lenses allows for proper work in extremely hard lighting conditions, from direct sunlight to almost complete darkness.
For outdoor operation, this kind of cameras has to be provided with outdoor housings with heaters, e.g. TH-847 M5405, and suitable mounts - TB-647 M5140.
As indoor devices, there may be used standard color cameras (without lens) e.g. VC-913D M1128 with M2230 lens, or dome models like C-3844-01A1 (vandalproof) M10735 or SN-IR141DC M10747.
Surveillance system for small shop - an article.

S/N ratio as indicator of camera's quality. With higher S/N (Signal to Noise ratio) we get camera having increased dynamic range, i.e. capability of shooting sharp and clear images in any conditions. It is widely assumed that good cameras should feature S/N not less then 48 dB.
The S/N ratio shows how many times useful signal is higher than unwanted noise determined by physical and technical construction. With S/N equal to 48 dB, the useful signal is 256 times higher than noise level. Too low S/N ratio would cause deterioration in image quality, visible as "snow" in the picture. It is especially noticeable in poor lighting conditions, when the useful signal has low levels.
Measurements of signals for determining S/N ratio are performed with switched off AGC (Automatic Gain Control). Active AGC keeps fixed level of output signal, dynamically improving S/N ratio in most situations. The image is clearer, but less natural. Switching AGC off, we get it more natural, but there may be visible some noise.

S/N	Image quality
>48 dB	practically no noise
37 dB	visible noise
30 dB	considerable snow
<26 dB	heavy snow

Color high resolution camera without lens SN-580C M11201 - S/N 50 dB; it may be utilized in poor lighting conditions (churches, temples, underpasses etc.)

Wireless IP camera PIXORD P400W. Small size IP camera P400W K1132 from PIXORD is capable of transmitting compressed MJPEG or MPEG-4 images. The image sensor enables quite high horizontal resolution of 520 TVL. An interesting function is possibility of direct recording of images via a web browser, besides through the enclosed free software. Installation of the camera is similar to other 802.11g devices.

PIXORD P400W K1132 camera.

The monitor for CCTV installer. Adjustment of camera and lens parameters can be a tiresome job, especially when the camera is not within easy reach. The work may be facilitated by employing service LCD monitor MIG-29 M3104. Due to small size of the device (3.5” diagonal) it is possible to conveniently adjust any camera, even when standing on a high ladder. Moreover, the monitor can be powered not only from the tested device/system, but also from the battery set that may be inserted into the additional pocket of the casing prepared for placement on the arm. It makes the job easier and safer.

LCD service monitor MIG-29 M3104

Choice of polarization of WiFi networks. There are two popularly used polarizations, the circular and linear ones. Circular polarization means that the end of the electric field vector circulates in the space. There is possible dextrorotatory or levorotatory version - they are orthogonal, i.e. they theoretically do not interact one with another.

 
Two possible circular polarizations.

When linear polarization is used, the electric field vector oscillates only in one plane, horizontal or vertical. Similarly to the above case, the two versions do not interfere, being also orthogonal. This future allows for doubling RF systems operating in the same area.

Wireless mesh networks. Wireless standard IEEE 802.11 has been supplemented with Mesh Network Architecture. The Mesh Standard, i.e. 802.11s, is still at development stage. The premise of 802.11s is creation of a protocol that will automatically configure the paths among access points on the "each to each" principle.
The idea of such network consists in linking the deployed over an area access points into a unity  - each node of the network may exchange data with its neighbors, making the information mesh that has only one unit connected to a fixed network.
Mesh networks having decentralized structure are highly reliable and comparatively cheap in implementation. Every node of the network cooperates with several adjacent nodes and can both receive and send data. If one of them is out of order, the neighbor will automatically take over its function, modifying the original route of the link.
As opposed to standard WDS, Mesh routers automatically detect their neighbors and learn the optimal route to every destination. It does not require manual configuration of each access point - there is no need to build a static routing table.
Mesh Network Architecture is characterized by scalability, auto-configuration, security and integrity. The ability of self-organization of Mesh networks brings down costs of building and expansion of the infrastructure. But the lack of an official standard for the networks poses a risk of incompatibility of access points produced by different manufacturers. The IEEE 802.11s specification should change the situation.

Mesh network concept.

Peking (Beijing). The capital and second greatest city of China in terms of the number of inhabitants (the first is Shanghai).
Among 10 highest TV towers in the world, three of them are in China. So far, the highest tower can be found in Toronto, Canada (CN Tower, 553m). But in 2009 the palm will be carried off by the being under construction Guangzhou TV & Sightseeing Tower in China, intended to be 610m high. The interesting and bold architecture of the tower you can view here.

January 2, 2007

Telecommunications - Technologies of 2006. What's new in 2007? HDTV and HSDPA are, in our opinion, Technologies of 2006 on European telecommunications market.
The past year saw a turning point in new television technology. Thedriving force was the World Cup, the event that attracted many viewers andcreated a mass market  for high definition transmissions. Satellite HDTV broadcasts are currently available in Great Britain, France, Italy,Belgium, Sweden, Luxemburg, Spain, Germany, Poland. In some countries (GreatBritain, France) there are being tested terrestrial HDTV transmissions, andcable operators have also started the process of implementation of thattechnology. After several years of delay, compared to the USA and leading Asiancountries, the last year promises to be beginning of pursuit for new quality,instead of sticking to the previous concept of DVB-T transmitting SDTV signals(with standard PAL resolution).
The battle of standards and struggle for the mobile web market iscurrently being won by cellular network operators. Having at their disposal bigfinancial and infrastructure potential, the operators quickly and effectivelyimplement HSDPA - wireless access to the Internet. On the other hand, someproblems with all-new devices and the necessity of building new infrastructureare the reasons why competing WiMAX is lagging far behind the HSDPA.
What trends will emerge in 2007? There is a pretty big chance for success of IP TV, thetechnology of TV distribution over the web. It is a big opportunity for fixedline segment, as the base of "Triple Play" services.

The producers of televisions have outdistanced HDTV broadcasters. At IFA in Berlin, Samsung presented family of HDTV 1080p sets that used DLP technology,
marketed as technology of the future for big size screens.

HDTV television on one chip. Observing development of electronics, there is seen continuous drive for miniaturization. New models with smaller dimensions provide even additional functions and possibilities, usually for lower price. One of the methods of miniaturization is powered by SoC (System on Chip) technology, that consists in implementing the whole device in one chip (IC). Such SoC version has been recently prepared for HD television. Broadcom company has developed IC marked BCM3563, in 65nm technology. It integrates all functions of standard HD 1080 TV set, also offering PC input. Although the chip has been devised for NTSC norm, it seems certain that in the near future we will see its PAL equivalent. So it will result in a further drop in prices of HD televisions.

Stimulation of imagination – VI competition "Engagingly about Antennas". Although the contest starts in June, we take into consideration pictures from all seasons, so it's high time for taking winter scenery pictures, especially when snowy winter wonderland goes somewhere to the North Pole... Subject of the photo contest is a challenge that, at first, seems to be difficult to be up to. What can be interesting in antennas?
But we hope the competitors will take up the task that, apart from having esthetic qualities, requires dash of imagination, grain of wit, and sometimes a certain measure of risk.
The works sent to the 2006 contest & terms and conditions of the newest VI edition.

"Ice-bound communication" by Lukasz Haremza

HD DVD from Microsoft. Together with development of HDTV there is seen in the market new generation of audio/video players. These are competing HD DVD and Blu-ray devices. Their quite high prices give opportunities for some promotion actions. Microsoft Corp. promotes its XBOX 360 game console by enabling purchase of external HD DVD player. Despite the fact that the player has to be bought with the mentioned console, the whole set (ca 600$ - Amazon) is still much cheaper than stand-alone HD DVD players sold on the market. The set allows the users to create multimedia center for playing HD discs, pictures, music, downloaded multimedia, and, of course, enables them to play the newest games.

A weak signal - to employ amplifier or change the antenna? Often in the case of low quality of picture installers use an amplifier with high gain. But the improvement seems to be dubious, or even some channels get additional interferences. Simply, increasing gain, one will not be able to improve quality of the original signal. It should be noticed that the main purpose of amplification in antenna installation is to compensate losses within distribution cable network.
Practically there should be employed amplifier having ca 10 dB higher gain than attenuation in installation, e.g. with 25 dB attenuation, amplifier having 35 dB gain would be optimal one.
In extreme cases, when the signal measured at matching transformer of the antenna is lower than 45 dBuV, an amplifier with higher gain may be used, to reach the level at outlets at least 60 dBuV.
The correct solution of weak signal problem is employing antenna with highest possible gain and directivity, e.g.:

• TV antenna DIPOL 44/21-69 Tri-Digital A2680

• TV antenna DIPOL 44/21-69eco Tri-Digital A2682

• TV antenna POLARIS 60/21-60 56,97 A3385

• TV antenna ATX 91/21-60 17dB 58,89 A3710

   
TV antenna DIPOL 44/21-69 Tri-Digital A2680 and its gain characteristics.

Satellite converters. Below we have prepared table that lists kinds of LNBs and gives their basic applications.

CCTV cameras in one-family homes. British market, probably the most developed one in Europe, has been dominated by compact cameras with IR illumination. They feature small dimensions, possibility of night operation, and easy assembling - all that is needed to gain high popularity among owners of the homes.
Compact cameras with IR illumination from n-cam series.

Compact cameras with IR illumination at a house in Birmingham.

IP CCTV equipment from Pixord. Well known on American and Asian markets Pixord company from Taiwan begins to penetrate European market, too. There is seen rising popularity of the units prepared for network operation, suitable for e.g. monitoring in businesses using efficient information networks. Set of such units (cameras) makes possible to build CCTV system without a cost of additional cabling, ensuring good quality for a reasonable price.
Compact IP camera P300 K1130 from Pixord uses 1/4'' CMOS sensor, and is capable of capturing 15 fps at VGA (640 x 480) resolution. In enables local recording on SD card, which is triggered by motion detection, giving opportunity of better management of the system. Built-in microphone allows registration of sound. Due to small size of the camera there is possibility of installation practically in any place.
Dipol is the trading partner of Pixord on Polish market.
IP CCTV cameras from Pixord.

Compact IP camera P300 K1130 from Pixord

Sharing of ADSL connection at home. Among home users, ADSL service is still popular technology of Internet access, despite some shortages, e.g. dynamically assigned IP address. There is often a need of supplying the connection to several computers, which can be realized by implementing the diagram below.
TP-Link TD-8840 N2905 contains ADSL modem compatible with ADSL/ADSL2/ADSL2+ protocols, and 4-port switch. Built-in DHCP server enables the user to implement the network. Additionally there can be incorporated Access Point AWAP-608 N2646, to create wireless network. For a laptop there may be used USB wireless adapter TL-WN321G N2920, or PCMCIA one TL-WN510G N2930, depending on the interface in the laptop or user's choice.
When using desktop computers a good choice is wireless card N2970.

Solution for sharing ADSL service.

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