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DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN
No.06/2015 (Feb. 9, 2015)
New lasers will speed up computers. Researchers from Forschungszentrum Jülich research center and the Paul Scherrer Institute in Switzerland have created the world's first semiconductor laser built from elements of the group IV of the periodic table. The new laser can be directly embedded into silicon integrated circuits. This will enable the creation of computer chips in which the information is transmitted primarily via light. Optical medium allows a much higher speed of data transfer compared with copper wires and is much more energy efficient.
In current chips the transfer of data between multiple cores and among logic segments and memory arrays is considered as a bottleneck in the rapidly developing computer technology. Optical data transmission offers the chance to solve the problem by increasing both the speed of the chips and their energetic efficiency.
"Signal transmission via copper wires limits the development of larger and faster computers due to the thermal load and the limited bandwidth of copper wires. The clock signal alone synchronizing the circuits uses up to 30% of the energy – energy which can be saved through optical transmission", explains Prof. Detlev Grützmacher, Director at Jülich's Peter Grünberg Institute.
Long-range telecommunications networks and data centers use optical connections for decades. They ensure very high throughputs, even over long distances. The transmission of optical signals is almost lossless and can simultaneously use different wavelengths. The currently manufactured semiconductor lasers used in electronic equipment are made up of elements of groups III-V (e.g. Gallium arsenide) and cannot be used for silicon chips. The life of such combinations would be very short due to the different coefficient of thermal expansion of the combined materials. An effective solution to this problem is the use of lasers constructed from the same group of periodic elements.
Historical and expected performance of silicon photonics
The group of scientists created a semiconductor laser made of germanium and tin. The laser had to operate at -183°C and be optically excited instead of direct power supply. The researchers have been working on solving the problem of the power supply and ability to work at room temperature, which would eliminate the need for additional equipment and cooling.
Splitting DVB-C signal. Digital cable subscribers are often faced with the problem of bringing the signal to the second room. In the best case (when the signal is not encrypted), it is enough to use a splitter and an additional DVB-C set-top box (unless the second TV has DVB-C tuner). However, in most cases the signal is encrypted and it is necessary to pay for second subscription or at least for multi-room service.
Often there is no need to watch different channels at the same time (e.g. single user wants to have the possibility to watch TV in another room or in kitchen). Under this assumption (each TV has access to the same TV channel currently selected on the STB), we present below 3 options.
Wireless Transmitter/Receiver Set: Signal TR-3000 (AV+IR@5.8GHz)Wireless Transmitter/Receiver Set: Signal TR-3000 (AV+IR@5.8GHz)TV Modulator TERRA MT-41Signal-HD HDMI Splitter 1x4
Three options of distributing a DVB-C channel to additional television(s)
  • option 1 - HDMI splitter Signal H3214 - the channel selected on STB is provided to other TVs or monitors via HDMI cables. The advantage of this solution is the possibility of watching HD channels on any of the TVs / monitors;
  • option 2 - TV modulator Terra MT41 R871741 - the best option when there is a coaxial cable between the rooms. As the modulator is connected to the analog A/V outputs of the STB, the STB has to provide signals simultaneously to the analog and digital outputs;
  • option 3 - A/V transmitter Signal TR-3000 R94110 - the best solution when the installation of any cable is difficult, impossible or unacceptable. The use of 5.8 GHz band practically eliminates the risk of any interference.
In the case of the options 1 and 2, the comfort of the user is considerably higher with the application of a remote control extender (e.g. Wireless Remote Control Extension 2079T/R R94116) allowing for control of the DVB-C STB from the other room. The wireless Transmitter/Receiver Set Signal TR-3000 R94110 (option 3) has built-in IR remote control extender.
Law issues relating to WLAN. Are we allowed to use antenna with extremely high gain, not breaking the law? It should be stressed that despite limitations on the use of the unlicensed 2.4 GHz and 5 GHz bands there are no rules on limiting the gain of antennas. So, why one obeys regulations having an antenna with 15 dBi gain, while another one breaks them using a 10 dBi antenna?
The answer to the questions follows directly from regulations concerning maximum level of Effective Isotropic Radiated Power (EIRP). Without a special license, in many countries the maximum EIRP = 100 mW, i.e. 20 dBm in the 2.4 GHz band, and 1 W (30 dBm) in the 5.47-5.725 GHz band. The same level of EIRP may be accomplished by many means:
EIRP [dB] = transmitter output power [dBm] - (loss of connectors [dB] + loss of cable [dB]) + antenna gain [dBi]
  • <= 20 dBm (in 2.4 GHz band)
  • <= 30 dBm (in 5 GHz band)
To keep the EIRP within the limits, the installer should properly adjust the relevant parameters: the power of the transmitter, cable type and length, gain of the antenna. Usually it is more advantageous to use a lower power transmitter and an antenna with higher gain than the other way round. A high-power transmitter with inadequate antenna (with too high gain) may exceed allowable EIRP.
Currently, many WLAN/Wi-Fi devices (APs) are integrated with antennas. There is no need for using coaxial cables and RF connectors. Such devices are usually connected with the system via UTP cable that can also ensure power supply (in the case of PoE equipment). The EIRP for such a device is the sum of the gain of the antenna and RF power (the RF power can be adjusted by software means).
Wireless Access Point: RouterBoard SXT-5HPnD (802.11n 5GHz 16dBi 2x2 MIMO level 3)
Integrated AP RouterBoard SXT-5HPnD 802.11n 5GHz 16dBi 2x2 MIMO level 3 N24115
The devil is in the details - cleaning the end faces of fiber optic connectors. The phenomenon of signal attenuation is the basic problem of the transmission of information over long distances. In the case of fiber-optic networks, an additional attenuation can be caused by factors such as inadequate precision of splices or too small bending radius. However, it happens that the attenuation of a link is too high, despite observing the basic rules.
A dirty ferrule end face (on the left) and the face cleaned with the NC-001 tool.
Improper cleaning of ferrule end faces may cause permanent scratches.
The sometimes forgotten or ignored factor increasing attenuation is a dirty ferrule end face. It may be the main and only reason for the trouble with the transmission of optical signal.
A good and cheap solution to this problem is to clean all terminations during the installation process. The ferrule end-face cleaner NC-001 L5916 removes dust, dirt and contaminants prior to mating a fiber optic connection. The special structure of the fabric accurately collects pollution, at the same time avoiding any scratching. Solid casing gives a good grip of the tool during operation. Interchangeable microfiber replacement reels L5917 ensure long life of the tool. The casing protects the cleaning surface against pollution during transport.
How to set recording triggered by motion detection in Signal NVR-2704. After logging on to the Signal NVR-2704 K2704, the administrator should select the following items in the NVR menu:
  • System Set -> Motion Detect, mark Switch Linkage and choose Channel No.,
  • System Set -> Rec Setup, choose Week and Every day and tick All Day check box.
The System Set window
The Motion Detection window
The Rec Setup window
After selecting these options, the recording triggered by motion detection will be activated.
How to set IP addresses of Sunell cameras with IPSearch app. If no DHCP server is found in the nework, Sunell IP cameras will set the default IP address and subnet mask. When they are connected to the same switch, the IP address conflict will prevent the connection to any camera via a web browser. Communication with each device separately and manual change of its address is an ad hoc solution reasonable only in the case of a small number of cameras.
Device Search Tool used for network configuration of Sunell IP cameras
In the case of large IP CCTV systems, the suitable solution is provided by IP Search application. It searches for all Sunell IP cameras in the LAN network and allows for quick change of IP addresses to eliminate conflicts. With this app, the user can also modify Subnet Mask, Default Gateway, DNS Server, User Name and Password of each camera. The Device ID allows for giving the camera any name, for instance connected with its location.
New products offered by DIPOL
19" RACK Panel J2848 for mounting two AXON PRO protectors J2845 (4x PoE+, 4x IN, 4x OUT) in a RACK cabinet.
Alarm Control Panel ROPAM NeoGSM-PS (main board)
Alarm Control Panel ROPAM NeoGSM-PS G7000 is a modern intruder alarm control panel that can combine the functionality of alarm system and simple home automation. It is the ideal solution for residential buildings and small commercial facilities. Compared to other systems of this category, the NeoGSM-PS control panel has a large amount of resources and functions, such as digital and analog inputs, digital outputs, two-way audio communication, GSM/GPRS communication, temperature measurement and recording, logical functions I/O and O/O. In addition, the functionality can be significantly increased by using expansion modules, such as the FGR-4 for sending MMS/EMAIL, VAR-1 gateway for integration with video intercom, or APm-Aero supporting wireless two-way communication e.g. with sensors.
Wireless AP and Controller: ROPAM APm-Aero
Wireless AP and Controller ROPAM APm-Aero G7030 has been designed to integrate wireless Aero devices with Ropam Elektronik devices, with the use of RopamNET bus. APm-Aero supports up to 8 wireless Areo devices Aero and automatically controls transmission power depending on the strength and quality of transmission. The programming and diagnostics of the device is performed via the dedicated PartnerGSM software, from the level of alarm control panel.
Worth reading
Satellite TV - one cable, four receivers. Satellite installations in one-family homes often require to use several cables. This is not a problem when the designer and building company have prepared spare conduits. If not, drilling and hammering walls in existing houses is a nuisance for the inhabitants.... more
Transmission over loooong distances - fiber optic equipment
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