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No. 33/2008 (Oct. 13, 2008)
There is no crisis in security - Security Essen 2008. The International Trade Show for Security and Fire Prevention took place in Essen between October 7 and 10. There were participating nearly 1000 companies, of which about 600 from Germany. In an era of crisis of exhibitions and financial and economic turbulence, it is an impressive number.
The fair in Essen is the second most prestigious event in European security industry - the No. 1 trade fair is recognized to be the IFSEC in Birmingham, taking place in spring.
The trade show in Essen confirmed the trends from Birmingham: strong market expansion of megapixel cameras, popular use of H.264 codec, and great development of software for image analysis.
A new thing is the emergence of IP cameras with the H.264 codec - Arecont, Hikvision (to date, manufacturers focused mainly on DVRs). Another new products are hybrid recorders, providing analog and digital channels, up to 16 + 16.
Network Video Recorders (NVR) have emerged as independent, but fully functional devices, so there is a chance that the dedicated devices will supplant PCs in IP CCTV applications in the future.
The number of software companies has also increased rapidly. Various needs of customers, as well as the lack of standards in the IP CCTV, makes it necessary to create software even for individual products.
However, this situation may change. The initiative taken in the spring of this year by Axis, Bosch and Sony - Open Initiative Network Video Interface Forum (ONVIF) aims to coordinate the development of standards for video surveillance systems. The organization, presenting the idea in Essen, encouraged other manufacturers to join this initiative.
The fair in Essen is the second most prestigious event in European security industry - the No. 1 trade fair is recognized to be the IFSEC in Birmingham, taking place in spring.
The trade show in Essen confirmed the trends from Birmingham: strong market expansion of megapixel cameras, popular use of H.264 codec, and great development of software for image analysis.
A new thing is the emergence of IP cameras with the H.264 codec - Arecont, Hikvision (to date, manufacturers focused mainly on DVRs). Another new products are hybrid recorders, providing analog and digital channels, up to 16 + 16.
Network Video Recorders (NVR) have emerged as independent, but fully functional devices, so there is a chance that the dedicated devices will supplant PCs in IP CCTV applications in the future.
The number of software companies has also increased rapidly. Various needs of customers, as well as the lack of standards in the IP CCTV, makes it necessary to create software even for individual products.
However, this situation may change. The initiative taken in the spring of this year by Axis, Bosch and Sony - Open Initiative Network Video Interface Forum (ONVIF) aims to coordinate the development of standards for video surveillance systems. The organization, presenting the idea in Essen, encouraged other manufacturers to join this initiative.
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IP megapixel cameras of ACTi, with H.264 codec | NAS (Network-attached storage) supports video recording |
A city of 100,000 statues - where is the tower? The city with the television tower visible in the photo was founded in the XI century B.C. For the first time it was the the capital of the country in 770 B.C. and remain the main city (with short breaks) for nearly 500 years. In 68 A.D. there were built the first Buddhist temple in China there - the White Horse Temple.
After a break of more than 200 years, the city again became the capital of China in 493 A.D. It was about that time when some people began construction of Longmen caves which contain over 100,000 statues of Buddha.
In which city is the tower? - The answer you can find at the end of this issue.
After a break of more than 200 years, the city again became the capital of China in 493 A.D. It was about that time when some people began construction of Longmen caves which contain over 100,000 statues of Buddha.
In which city is the tower? - The answer you can find at the end of this issue.
The city of 100,000 statues - the place where the tower is situated
Requirements for input signal in multiswitch systems. Large multiswitch systems require use of many amplification stages that introduce additional noise. Increase of noise lowers the S/N (C/N) ratio, directly influencing BER. Its value of 10-4 (in a subscriber outlet) means loss of reception, due to impossibility of regenerating the original signal, despite redundant coding employed.
To avoid any problems, BER level at the LNB output should be about 10-8. Proper BER level can be obtained by using a large satellite dish, e.g. 110 cm A9658. This is the best and cheapest way of providing quality signal - simply there is only one dish for one satellite.
To avoid any problems, BER level at the LNB output should be about 10-8. Proper BER level can be obtained by using a large satellite dish, e.g. 110 cm A9658. This is the best and cheapest way of providing quality signal - simply there is only one dish for one satellite.
Galvanic isolation of home receivers from cable TV network. Residual currents are often the reason of unwanted effects in the receivers connected to a cable TV network. They include hum or unexpected disconnection of power supply due to trip of residual-current device (RCD, RCCB, GFCI, GFI, ALCI, etc). The trip current is caused by the difference of potentials between the shield of the coaxial cable and the neutral conductor of the electrical wiring, typical for large networks. A perfect solution to this problem is use of galvanic isolator R48605. It has very low attenuation of the signal - 1.5 dB.
Optimum cabling solutions (S/MATV) for multi-family buildings. Cabling is the part of signal distribution system in a building that is extremely difficult to exchange. In practice, it often cannot be easily modified even if the cables are arranged in tubes. So it is important to design the cabling in such a way that allows possible extension of the distributing system without a need of modifying the cable layout.
If, for economical reasons, the first stage includes only MATV distributing system, the cabling should be prepared for future introduction of satellite signals.
The most flexible multiswitch installations in multi-story buildings are based on 9-cable system. Below there is an example of using such cabling in multiswitch system.
Of course, at the beginning the cabling may be used only for distribution of terrestrial signals, without employing multiswitches. At this stage there are needed only Signal splitters and taps, and one of the nine cables.
The cables for multiswitch systems should ensure very good shielding (class A) and impedance matching. We can recommend TRISET cables.
If, for economical reasons, the first stage includes only MATV distributing system, the cabling should be prepared for future introduction of satellite signals.
The most flexible multiswitch installations in multi-story buildings are based on 9-cable system. Below there is an example of using such cabling in multiswitch system.
Of course, at the beginning the cabling may be used only for distribution of terrestrial signals, without employing multiswitches. At this stage there are needed only Signal splitters and taps, and one of the nine cables.
The cables for multiswitch systems should ensure very good shielding (class A) and impedance matching. We can recommend TRISET cables.
Bus cabling requires high-quality TRISET-11 E1027 cable
CCTV images in S/MATV and cable TV systems. Using dual-sideband (DSB) modulators, e.g. MT-21P R871721, there is the need to secure four neighboring channels for each active CCTV channel. The two outermost channels ensure the gap to TV channels, whereas the additional one has to be left for the image signal (the sideband signal).
The diagram below shows the layout of the channels. The useful transmission is only performed in the band signed "modulated signal".
Such wide spacing is required due to filter slope characteristics of input circuits of TV sets. For that reason the neighboring channels cannot carry high-level interferences - they must be free or ensure very strict norms like those in cable TV networks. Otherwise, they would cause visible interferences, in any case when the signal level of a neighboring channel exceeds the useful signal by more than 3 dB.
In the case of SSB modulators MT-30A R871731 or MT-30C R871733, the transmission will require reservation of three channels only, as image channel has been suppressed.
The diagram below shows the layout of the channels. The useful transmission is only performed in the band signed "modulated signal".
Such wide spacing is required due to filter slope characteristics of input circuits of TV sets. For that reason the neighboring channels cannot carry high-level interferences - they must be free or ensure very strict norms like those in cable TV networks. Otherwise, they would cause visible interferences, in any case when the signal level of a neighboring channel exceeds the useful signal by more than 3 dB.
In the case of SSB modulators MT-30A R871731 or MT-30C R871733, the transmission will require reservation of three channels only, as image channel has been suppressed.
Transmission of CCTV signal in the channel marked "modulated signal"
Transmission of TV signal up to 400 m. Audio and video signals can be transmitted via a UTP/FTP cable with the use of TR2P+2AU transmitter/receiver M1662. The set of two such devices can be used e.g. for transmitting A/V signals from a VCR, DVR etc. to a TV set located in a different room, as well as for transmitting IR signal controlling the source device (using IR remote control extender Signal-Link R93109, see the diagram below).
The maximum distance (without noticeable loss of quality) is 400 m. The transmission path contains the two double audio-video transformers connected with twisted-pair cable and the Signal-Link set. The audio and video signals are transmitted from the source device to the television, the control signal travels in the opposite direction.
The maximum distance (without noticeable loss of quality) is 400 m. The transmission path contains the two double audio-video transformers connected with twisted-pair cable and the Signal-Link set. The audio and video signals are transmitted from the source device to the television, the control signal travels in the opposite direction.
Transmission of TV and control signals up to 400 m
Some IR lighting tips. IR illuminators are used in CCTV systems that have to maintain monitoring capability in total darkness. Infrared lamps, as well as the sources of visible light, have different angles and power of radiation. These parameters directly influence the range of operation.
The infrared wavelengths are within the limits of 700-1000 nm. With the increase of the wavelength, the light of a glowing lamp or IR LED is less visible to the human eye, but it also decreases the sensitivity of the camera. The lamps have built-in infrared filters: 750 nm (the light is yet visible), 830 nm (almost invisible), 950 nm (completely invisible to the human eye).
IR illuminators are made as LED or halogen lamps. The former ones are more durable, but have certain power limits.
There are also lenses specially prepared for cooperation with IR illuminators. They feature IR correction enabling precise imaging (e.g. M2136, M2137, M2139, M2157). As usual, the lenses should have the lowest possible F-number.
The infrared wavelengths are within the limits of 700-1000 nm. With the increase of the wavelength, the light of a glowing lamp or IR LED is less visible to the human eye, but it also decreases the sensitivity of the camera. The lamps have built-in infrared filters: 750 nm (the light is yet visible), 830 nm (almost invisible), 950 nm (completely invisible to the human eye).
IR illuminators are made as LED or halogen lamps. The former ones are more durable, but have certain power limits.
There are also lenses specially prepared for cooperation with IR illuminators. They feature IR correction enabling precise imaging (e.g. M2136, M2137, M2139, M2157). As usual, the lenses should have the lowest possible F-number.
Monitoring of separate shop floors. Video surveillance of shop floors based on wired CCTV system can be difficult to implement due to extensiveness of the area and problems with installing cables in operating industrial plant.
An ideal solution seems to be application of IP cameras enabling easy installation of distributed monitoring systems. In industrial environment the backbone of the system can be a WLAN operating in 5 GHz band. The wireless network can be based on highly-efficient Aphelion and/or Raptor devices. In the toughest industrial conditions there can be employed the cameras P412 K1331, P428 K1136, P463DW K1236, whereas in offices and less polluted sites - the cameras P400 K1131.
An ideal solution seems to be application of IP cameras enabling easy installation of distributed monitoring systems. In industrial environment the backbone of the system can be a WLAN operating in 5 GHz band. The wireless network can be based on highly-efficient Aphelion and/or Raptor devices. In the toughest industrial conditions there can be employed the cameras P412 K1331, P428 K1136, P463DW K1236, whereas in offices and less polluted sites - the cameras P400 K1131.
Block diagram of IP CCTV system for an industrial plant
Half-power beamwidth of an antenna. The half-power beamwidth is the angle between the half-power (-3 dB) points of the main lobe, referenced to the peak power of the lobe (in the main axis, for the analyzed plane).
A common mistake is the assumption that the radiation outside this angle can be neglected. For example, in the case of two client stations at an angle distance of 30 deg, the installer usually looks for an antenna with half-power beamwidth well above this value, whereas it is enough to employ a device with the beamwidth about 30 deg.
In practice, it is important to know the pattern of the antennas, to optimize the wireless network. Various types of antennas can have identical half-beam angle (e.g. 28 deg), but different patterns, so they may perform differently in the system. For example, one antenna can have -6 dB points at the angle distance of 64 degrees, another one 36 deg. So the first one covers a wider area. It is sometimes favorable (in the case of base station), and sometimes should be avoided (as a client antenna it would be more susceptible to interference).
A common mistake is the assumption that the radiation outside this angle can be neglected. For example, in the case of two client stations at an angle distance of 30 deg, the installer usually looks for an antenna with half-power beamwidth well above this value, whereas it is enough to employ a device with the beamwidth about 30 deg.
In practice, it is important to know the pattern of the antennas, to optimize the wireless network. Various types of antennas can have identical half-beam angle (e.g. 28 deg), but different patterns, so they may perform differently in the system. For example, one antenna can have -6 dB points at the angle distance of 64 degrees, another one 36 deg. So the first one covers a wider area. It is sometimes favorable (in the case of base station), and sometimes should be avoided (as a client antenna it would be more susceptible to interference).
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Advanced settings of the TP-LINK TD-W8910G N2901 Access Point. To configure optimum settings of this Access Point, the user can in the Wireless >> Advanced menu:
- change wireless standard of the AP,
- change the operating channel,
- switch on QoS for WLAN interface,
- change advanced settings of the AP. Some tuning is allowed only in the case of incompatibility of transmitted data.
Atmospheric discharges - protection of wireless networks - part 1. Many antennas protect in a way the cooperating transceivers (APs) against atmospheric discharges. These antennas are DC short-circuited. However, it is not a sufficient solution in the case of a direct strike.
A good solution is mounting the antenna on a mast/tower, the base of which is connected to the lightning conductor and grounding system. Additionally, the mast/tower has to be extended well above the antenna (or the antenna should be mounted well below the top of the mast/tower). In the event of a direct lightning strike it carries the electric charge to the ground.
A good solution is mounting the antenna on a mast/tower, the base of which is connected to the lightning conductor and grounding system. Additionally, the mast/tower has to be extended well above the antenna (or the antenna should be mounted well below the top of the mast/tower). In the event of a direct lightning strike it carries the electric charge to the ground.
Between the AP and the antenna there should be installed a lightning protector:
A picture from IQinVision camera
The lightning protector must definitely be grounded via the clamp and specified copper wire.
SAT Krak 2008 - Krakow, October 16-18, 2008
The lectures organized by DIPOL during the SAT KRAK 2008
DIPOL at SAT KRAK 2008
The lectures organized by DIPOL during the SAT KRAK 2008
DIPOL at SAT KRAK 2008
Luoyang. The city was formally the capital city up to the tenth century, but since the seventh century its significance was disappearing in favor of the second capital city - Chang'an.
Longmen Grottoes are rock-cut Buddhist statues. The niches extend over one kilometer. The complex was listed by UNESCO in the list of World Heritage Sites in November 2000.
Longmen Grottoes are rock-cut Buddhist statues. The niches extend over one kilometer. The complex was listed by UNESCO in the list of World Heritage Sites in November 2000.
The Longmen Grottoes near Luoyang
We have written about:
Antenna system measurements. Knowledge of signal parameters, among others - differences in levels of useful signals, signal levels in subscriber outlets, BER, level of noise and interferences - allows to prepare optimal design and verify actual results...
- archive DWR of Nov. 19, 2007
Home and business Wi-Fi networks - applications of TP-Link family. ... When we want to use wireless Internet connection we need device supporting WISP mode...
- Library
Monitoring of dispersed locations - how to lower cabling costs. (Use of UTP cable for video transmission). When the distances between cameras and the monitoring center are long, the cost of cabling is a significant part of the total cost of the whole undertaking. As an example, video transmission from four cameras, located 300 m from the center, means that the coaxial cable will cost...
- archive DWR of Sept. 10, 2007
Index of published issues
Antenna system measurements. Knowledge of signal parameters, among others - differences in levels of useful signals, signal levels in subscriber outlets, BER, level of noise and interferences - allows to prepare optimal design and verify actual results...
- archive DWR of Nov. 19, 2007
Home and business Wi-Fi networks - applications of TP-Link family. ... When we want to use wireless Internet connection we need device supporting WISP mode...
- Library
Monitoring of dispersed locations - how to lower cabling costs. (Use of UTP cable for video transmission). When the distances between cameras and the monitoring center are long, the cost of cabling is a significant part of the total cost of the whole undertaking. As an example, video transmission from four cameras, located 300 m from the center, means that the coaxial cable will cost...
- archive DWR of Sept. 10, 2007
Index of published issues
