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

Photonic modem for communication in outer space.

Scientists from NASA announced plans to build the world's first photonic modem. It will be part of a program called Laser Communications Relay Demonstration (LCRD) focused on the creation of high-speed connections between devices in outer space and Earth with the use of lasers. Laser communication has been identified as the most promising because of the possibility of sending more information (10-100 times) with lower power consumption and less weight of the devices compared with radio systems. Tests of such connections had already been carried out, and even record data rates were achieved a bit of time ago, in 2013. The result of the Lunar Laser Communication Demonstration (LLCD) project was a transmission of data from the Earth to the Moon (ca. 400,000 km) at data rates 622 Mbps (downlink) and 19.44 Mbps (uplink), an accomplishment far beyond the capability of radio systems.

A visualization of the test data transmission between the Earth and the Moon with the use of lasers -
Lunar Laser Communication Demonstration (LLCD) project
(source: nasa.gov)

The photonic modem is to be placed on spacecraft in low Earth orbit and is to act as a relay station between the Earth and outer space. NASA has decided to develop devices based on photonics (photonic processor with laser and other components integrated in one chipset).

The project of an LCRD relay station with photonic modem
(source: nasa.gov)

NASA uses radio frequency links for extraterrestrial communication since 1958. The new communication system will be tested in outer space since 2019.

Defog function in Hikvision IP cameras.

Hikvision cameras provide a number of image processing functions. Defog is one of the interesting and useful functions embedded in cameras of the 4th and 6th series, as well as in the majority of PTZ cameras. It improves image quality in the presence of adverse weather conditions such as fog or smog. After its activation, the camera analyzes the contrast of the image and depth of field in different points of the scene. On this basis, it creates a special digital filter that enhances image details normally hardly visible or even invisible for the human eye due to haze. This way, the digitally processed image is significantly better than the original one.

Comparison of images from a Hikvision camera taken during dense fog,
on the left - without additional processing, on the right - with Defog function.

Sunell thermal imaging camera.

The Sunell SN-TPC4200KT/F K1606 thermal infrared camera belongs to the high class of this kind of equipment. High quality infrared detector, proprietary algorithms of data processing plus a new generation lens with high transmittance of thermal radiation, form the basis for excellent performance in any weather conditions (smoke, fog, rain etc.). The thermal camera can operate day and night without any additional lighting, so it can easily be camouflaged and made practically invisible for intruders.

The "Thermal_V3.5.00R" or higher firmware version implements all the mechanisms of temperature detection, threshold settings, regions of interest directly in the camera. It means that all the functions can be executed without using a computer and/or additional software. When the camera is connected to any IP NVR supporting ONVIF protocol, all temperature markers can be recorded along with the images. After logging in to the camera via IE web browser, the user gets live image with the highest temperature mark. Additionally, the user can define up to five regions of interest, with the same characteristics as ​​the main window. However, the thresholds and kinds of temperature alarms can be set independently. By default, the information about the maximum temperature in each region is displayed in the lower left corner of the image. The messages on exceeding certain temperature thresholds appear in the preview window as well.

In addition, it is possible to use temperature alarm outputs to control external devices (IP NVRs, alarm systems, PLCs). After connecting the camera to an IP NVR and switching on motion detection, it is possible to monitor large areas and detect moving intruders with a single camera, without the need for long-range IR illuminators. Sample images from the thermal camera are shown below.

Isolation between inputs determines the quality of multiswitches.

The isolation between inputs is one of the most important parameters influencing the quality and class of a multiswitch. A good isolation (>30 dB) practically eliminates crosstalk between inputs and thus prevents mutual interference of signals from each input, which could lead to a decrease in signal quality (an increase of BER). In the case of inadequate isolation, some transponders can be received flawlessly without any problems, but the reception of other channels may be unstable or even end up in a message like "no signal". This is caused by different signal levels of various satellite transponders and increased risk of interference in the case of a lower level.

TERRA MV-924L R70874 multiswitch

In terms of isolation, the leading devices are TERRA multiswitches. Guarantying minimum level of 30 dB, the manufacturer in practice provides multiswitches with isolation above 35 dB. The very high level of isolation achieved thanks to excellent construction and high quality materials allows for building very extensive multiswitch systems that require high signal levels. For example, with a VL signal from a Quatro LNB at the level of 75 dBμV and isolation of 35 dB, the level of interference at any other input is limited to 40 dBμV (75 dBμV - 35 dB = 40 dBμV). The level will be further lowered due to attenuation of the distribution system (cables, connectors, outlets) and finally will be below the sensitivity of satellite receivers.

Mobile Internet.

Wireless Internet access via cellular networks is an increasingly popular service. The growing popularity of this service among subscribers is the result of mobility, higher throughput and lower prices. The absolute highlight is LTE technology that enables the achievement of data rates similar to those in landline /cable or WiFi networks.

Depending on the cellular operator and transmitter, the access to the Internet can be based on different technologies. The following table lists the most popular technologies of wireless internet access used in the infrastructure of mobile operators in Europe and their maximum data transfer rates.

LTE technology is flexible both in the terms of the frequency range and bandwidth of the transmission channel. LTE networks can operate in frequency bands from 700 MHz (non-urbanized areas - longer range) to 2.6 GHz (metropolitan areas - higher capacity). An important element of LTE is MIMO technology (Multiple Input Multiple Output) increasing transmission efficiency by employing multiple antennas on both ends of the transmission links.

If a mobile device (modem) is far from the base station or is "shadowed" by some obstacles, the communication can be improved by connecting an appropriate antenna. Some popular LTE antennas are shown below.

ATK-LOG ALP LTE MIMO 2x2 antenna (800-3000 MHz) with 10 m cable terminated with SMA plug - A7054_10

Ultimode media converters - system diagnostics.

Ultimode media converters transmit Ethernet signals via optical fibers. These "plug and play" devices do not require any configuration. In the case of some problems, the reason for them is usually the optical part of the system.

In the event of any problem, the first step of the installer should be the verification of LED indicators in the converters deployed on the both ends of the link.

If the LEDs indicate a problem with the fiber-optic path, the fiber optic cable should be checked with a visual fault locator, e.g. L5935. No transfer of visible light indicates an improper installation. If the verification with the visual fault locator does not show any problem with the optical cable, a more detailed examination is needed, preferably using a reflectometer.

Ethernet media converter M-023G L10025 -
the output level is -3.46 dBm, which is compliant with the declared range (-8 ... -3 dBm)

Professional WiFi networks in buildings. DIPOL has extended the product range of WiFi devices by TP-LINK access points of EAP series. They provide flexible and secure solutions for the implementation of wireless networks that are easy to install and manage. The APs can be easily mounted to walls or ceilings. WLAN configuration and management are simplified through centralized management software. TP Link EAP devices also provide captive portal and automatic RF management, making them ideal for high-density, demanding business environments, such as campuses, hotels, shopping malls, offices... >>>more

An example of the deployment of EAP access points

New version of SatNet software