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

A breakthrough in photography - image sensor from graphene.

It is not the CMOS, CCD, or Foveon technology from Sigma that may be the future of photography, both in "serious" applications in "traditional" still cameras and in popular use in mobile phones. A team of researchers from the University of Nanyang in Singapore, led by Assistant Professor Wang Qijie, has developed a light-sensitive layer from graphene. This layer can trap photo-electrons for a longer time and the accumulated charges provide a stronger electrical signal. This means improved sensitivity, so important in low-light conditions.

The developers of the graphene sensor with the result of their work.
The tiny, transparent piece can be a milestone in the development of digital photography.
[source: sciencedaily.com]

The sensitivity of the new type of image sensor is about 1000 times higher than in the case of earlier graphene sensors and about 10 times better than that of CMOS sensors used in digital cameras. An important factor is also the amount of energy needed by the new sensors - they operate at much lower voltages and the total power consumption is ca. 10 times lower that in the case of traditional technologies.

An important advantage of the new sensor is the fact that it can be manufactured using the existing production lines for CMOS circuits. In mass production, the price of the graphene sensors can be several times lower than of the currently produced CMOS devices.

Media converters - the best protection against lightning surges and other overvoltages.

Network equipment responsible for the transmission of data in companies is usually a major investment. Financial aspects also include any losses that could be caused by the failure of the ICT systems during everyday operations. Special efforts are required to minimize the risk of damage to the servers.

Two ULTIMODE media converters connected by a short patch cord make a simple, efficient and reliable method of securing network and computer equipment against any voltage surges.

Optical fiber is an electrical insulator. It provides excellent electrical isolation between devices, while allowing high data transfers. In order to fully protect network and computer equipment from external voltage surges, many users apply two media converters connected via a patch cord, just before the server cabinet.

For this application, the best choice is to use Gigabit Ethernet media converters cooperating with two multimode fibers (duplex), which are cheap and eliminate the need of optical attenuators at the extremely short distance, such as M-023G L10025.

SMATV system in a multistory building.

The system allows for the reception of all available terrestrial TV channels and satellite channels from one satellite position (e.g. Hotbird 13E). All the channels are available in each subscriber outlet. The system has been based on TERRA MSV multiswitches. The extension of the main cable bus into subnetworks is made with SSQ-508 R70520 splitter and SS-510 R70520 taps.

The DVB-T signals have been received by directional UHF antenna Dipol 44/21-69 Tri Digit A2670 featuring high energetic gain (14-16.8 dBi). The signals are amplified by a set of channel amplifiers TERRA at420 R82510 (optionally it could be four-channel amplifier Terra at440 R82511). The amplifiers strengthen and equalize the signal levels at the input of the installation, which is crucial for such a large distribution network.

The project of the multiswitch system designed with the use of free SatNet software
- distribution of DVB-T and satellite signals to 108 subscriber outlets ( R694100).
Designing SMATV systems with SatNet software from TERRA.

One of the most important parameters in multiswitch systems is the isolation between paths carrying signals from different polarizations/bands. The key issue is the screening efficiency of the coaxial cables and the quality of the active and passive devices. Among coaxial distribution cables, the best screening efficiency is ensured by the TRISET-113 E1015 cable. Its 92% braid filling factor plus aluminum foil result in 100 dB screening efficiency (between A+ and A++ class). The die-cast housings of the TERRA MSV multiswitches protect the circuitry against interference caused by external electromagnetic fields.

A very big advantage of this solution is its flexibility. A similar system can be used in any building and layout of the outlets. Thanks to the wide range of TERRA multiswitches, the designer has virtually unlimited possibilities to choose the right topology and equipment. If needed, any system can be easily modified in the future.

How to protect CCTV equipment against overvoltages?

One of the most common causes of CCTV equipment failures are lightning surges. The systems with the highest risk are those with long external cables which can generate high voltages even in the case of large distances from lightning strikes. The overvoltages are dangerous for the devices on both sides of the transmission lines.

Devices that are connected via coaxial cables should be protected by single ( M1701) or quadruple ( M17014) CCTV video surge protectors. Devices connected with twisted pair cables require to use AXON protectors. AXON AIR NET protector J2835 is designed for surge protection of devices connected to Ethernet 10/100/1000 Mb/s networks via overhead UTP/FTP cables, AXON PoE Net Protector provides surge protection of devices connected to Ethernet 10/100/1000 Mb/s networks and utilizing unused pairs of the UTP/FTP cable for power supply, AXON ADSL Protector J2810 protects ADSL equipment connected to a telecommunications line.

Surge protectors located on both sides of transmission lines should be placed as close as possible to the protected devices. The basic condition for an effective operation of the AXON protectors is to connect the green&yellow cable to the ground (not to a lightning conductor) or to the protective earth/ground conductor (PE) of the AC power network.

Protection of CCTV devices connected via coaxial and UTP/FTP cables

64 cameras with 5 MP resolution - top video surveillance solution at affordable price.

NUUO Titan NVRs are innovative plug&play devices in housings compatible with RACK system. They are designed for full management of IP CCTV systems. The main functions include live monitoring, recording of video streams, playback of the archives. NUUO NVR Titan NT-8040(R) K4804 utilizes new File Ring recording engine which is optimized for storing and retrieving large amounts of megapixel video data. Thanks to a new way of downloading and archiving the data, the NVR is capable of transfers up to 250 Mbps, thus servicing up to 64 5-megapixel H.264 cameras.

Aside from archiving the surveillance data, at the same time the NVR must provide online the live video streams from the cameras as well as any required archival materials to the client stations. It could be impossible using a single Gigabit Ethernet port. To split the data streams from the cameras from the data streams transmitted to the client workstations, the NUUO NVR has been equipped with two Gigabit Ethernet ports. It ensures higher reliability of the system and lowers the risk of overloading the network. Additionally, if one of the network cards broke down, the second could temporarily handle the whole network traffic.

The architecture of a system based on the K4804 NVR and Sunell cameras K1695, K1637

The TP-LINK TL-SG3424P JetStream N29961 switches organize the LAN network and supply power to IP cameras compliant with PoE 802.3af standard. Depending on the number of the cameras and the distance between the switches, they can be connected via GbE ports (up to 100 meters) or via SFP modules (to be bought separately, the distance can reach even 20 or so kilometers).

A single K4804 NVR can serve 128 connections with cameras (e.g. each of 4 clients can simultaneously monitor 32 different cameras) and play back 64 channels (e.g. each of 8 clients can simultaneously play back 8 recordings).

Operation modes of home/SOHO access points.

Access Point (AP) - it is the basic mode that allows wireless communication between any client equipped with a wireless card/adapter and the AP. The users (clients) connect to the wireless network in Infrastructure mode.

The structure of a home network: AP + repeater

In the case of a larger house the range of one AP can be insufficient. The problem can be solved by using another device, operating in Repeater (regenerator) mode, and used for extending the wireless network. The device receives the desired stream of data and sends it further. This mode is often used in larger buildings for ensuring better coverage. Due to the way of work, the maximum throughput of the AP is decreased by 50%. This device configuration has the advantage over two devices working in AP mode that the client devices don't have to switch between APs, e.g. when a user is moving around the house with a handheld.

Measurements in optical systems. Any installer wanting to start working with optical fibers must acquire new tools, among them an optical meter, a very important device, quite different from meters used in copper systems... more

Optical Power Meter GRANDWAY FHP1B02
L5821

Distribution of digital terrestrial television in an apartment building. To receive and distribute DVB-T broadcasts, the apartment building with four staircases has been equipped with a set of Terra channel amplifiers that filters and amplifiers signals received by DIPOL 44/21-69 Tri Digit A2670 antenna. The set consists of two twin channel amplifiers at420 R82510 and broadband amplifier ma400 R82520. The modules are placed on R82538 rail and powered from DR-60-12 R82532 power supply unit. The set, capable of amplifying four DVB-T multiplexes, provides at its output stable (AGC) high level signals. Additionally, the residents have access to FM radio broadcasts received by Dipol 1RUZ PM B A0221 antenna... more

Diagram of the DVB-T distribution system in the building with 4 staicases and 64 apartments

Power over Ethernet in large IP CCTV systems. IP cameras K1620, K1630, K1670, K1680, K1690, K1691, K1695, K1698 that are compatible with IEEE 802.3af (PoE) standard can be powered over the network cable. The application of this option eliminates the need for using power supply adapters with 12 VDC output plus additional cabling. It simplifies the installation process and lowers the cost of the system. All cameras connected to TP-LINK TL-SG3424P JetStream N29961 managed switch form LAN network and can get power supply (PoE 48 VDC)... more

The concept of IP CCTV network with PoE