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

Superconducting camera with 400,000-pixel resolution.

Researchers from the National Institute of Standards and Technology (NIST) have unveiled a new camera with a resolution of 400,000 pixels that could redefine our view of the Universe. The researchers' creation of a new camera with a resolution of as many as 400,000 pixels represents a huge advance in this field of science. That is 400 times more than in previous prototypes. The device offers unparalleled precision in capturing faint blue light. Unlike traditional cameras, which use solid-state sensors to capture a broad spectrum of light, superconducting cameras can detect single photons, making them extremely effective at capturing signal from weak light sources. The cameras are cooled to near absolute zero. At this temperature, electric current flows without resistance, a phenomenon known as superconductivity. When a photon (a particle of light) strikes the camera's detector, it disrupts the flow in a particular pixel. By mapping this interference, scientists can create a complete image of the object viewed by the camera.

Until now, adding more pixels to superconducting cameras has been a huge challenge. For each pixel in the camera to function properly, it needs its own connection to the cooling system. With hundreds of thousands of pixels, this seemed almost impossible. By combining signals from multiple pixels into just a few nanowires, the team managed to circumvent this problem. A single wire can read data from an entire row or column of pixels at once. This is a bit like a game of tic-tac-toe, where each point of intersection is a pixel. Detectors can spot differences in the arrival time of signals on the order of 50 trillionths of a second. They can also count up to 100,000 photons per second hitting the grid. Using this approach, the team was able to quickly detect which pixel is activated by a photon. With such a powerful camera, the possibilities are enormous. Over the next year, the team plans to increase the sensitivity of the camera, hoping to capture virtually every incoming photon.

Intelligent motion detection in Sunell devices.

The most important task of a motion detection system is to detect the entry of a person or a vehicle to the monitored area. Each motion detection can generate an alarm event (e.g. notification to the user, guard or operator) and start video recording.
Traditional motion detection was based on changes in the light intensity reaching a pixel sensor(or larger clusters of pixels). Each change of light triggered detection so the system also caught the movement of objects that are not important from the point of view of security. Ordinary motion detection was sensitive to, for example, the movement of leaves in the wind, passing insects, birds, shadows or precipitation.

The intelligent motion detection function of Sunell devices works with data from traditional detection, but analyzes events to detect the presence of people or vehicles. Alarm notifications from intelligent motion detection are configured independently of traditional detection, so only correct notifications are sent. This increases the performance of the entire system and reduces the number of false alarms reaching the user. In addition, recordings stored on a compatible DVR can be easily searched for the presence of people or vehicles.

DVB-T2/HEVC terrestrial television in a SMATV system with legacy DVB-T/MPEG-4 standard receivers.

The need to receive DVB-T2/HEVC signals should not make it necessary to replace the receiving antenna. In by far the majority of cases, such a system requires an upgrade on the receiver side – if the TVs do not support the DVB-T2 standard with the HEVC codec (also known as H.265 or MPEG-H part 2) and do not process audio encoded according to the E-AC-3 standard (also known as Dolby Digital Plus or DD+). While in the case of a small system with one or several TVs there should be no problem (it is enough to buy a DVB-T2/HEVC decoder that is connected via HDMI output), it may be quite an issue for larger number of TVs, especially in boarding houses, hotels and the like.

Reflectance and reflection attenuation of the connector.

Reflectometric measurement provides a range of information about the measured line. One of the measured parameters is the so-called reflectance of a given incident analyzed in the case of reflective elements: connectors and mechanical splices, among others. By definition, reflectance is the ratio of the power reflected by an object to the power incident on that object, expressed in decibels. Since the power of the reflected signal will always be less than the power of the incident signal, reflectance values will take on negative values.

The concept of reflectance is often confused with the so-called return loss (RL). The definition of this parameter is virtually identical, taking into account the minus sign: RL = -10log (Podb/Pwe) describing the value of attenuation to which the reflected signal is subjected in a sense.

For example, according to IEC 61300-3-6, the best connectors (the so-called "Grade 1") should have a minimum reflective attenuation of 60 dB. The higher the value, the better. This corresponds to reflectance values of -60 dB and lower. The lower the value, the better. This means that the power of the reflected signal is a million times less than the power of the signal incident on the connector!

Batch activation of Hikvision network devices and changing their IP addresses with SADP.

SADP ( Search Active Device Protocol) is free and easy to use software designed to search for Hikvision IP cameras, DVRs and video intercoms on the local network. Using it you can modify their basic network parameters, activate devices and change or restore passwords. SADP is particularly useful when building large CCTV or video intercom systems. Newly purchased devices have to be activated by assigning passwords. In addition to that, the IP addresses of the devices are repeated so there would be a conflict of IP addresses when all of them were connected to the network at the same time. While in the case of a few devices it is possible to connect them one by one, activate and change IP address via a browser (if the device has built-in webserver), for large e.g. CCTV systems with 32 IP cameras, it would be very laborious and time-consuming. After connecting all devices, SADP running on the local network will detect them as inactive. Selecting them all , allows for a quick batch activation of the devices by assigning an administrator password. For DVRs, it is also necessary to enter the password for activating cameras. Upon acceptance, a window will appear confirming the activation of the devices.

When this step is finished, you can proceed to batch addressing of the devices. To do so, select all the devices and complete the network parameters, as shown in the following image. The devices will be addressed one by one starting from the IP address that has been entered. When the password with which the cameras have been activated is entered, a window with information about the changes will appear.

Visibility in wireless networks.

It is important to realize that the range of a wireless network depends on many factors, some of which we can influence and others are unknown. Fresnel zone is one of the most important concepts appearing in radio subjects you absolutely must be familiar with. It is the area actively involved in the transmission of radio signal energy. The shape of this area in longitudinal section is an ellipse, and in cross-section it is a circle. The radius of this circle varies along the length of the entire radio link and assumes a maximum value in the middle of the distance between the antennas. The first Fresnel zone is the most important, since it is in this zone that almost all the energy of the radio signal is transmitted.

The cross-sectional radius of each Fresnel zone is largest in the center of the zone and decreases to the point of the antenna at each end. The maximum radius of the first Fresnel zone is often useful information. It occurs halfway between the transmitter and receiver.

Objects (hills, trees, buildings, etc.) located in Fresnel zones have a big impact on wave propagation (especially if they are in the first zone). The more of them and the larger they are, the worse the conditions for signal transmission. For links with improved operational reliability, the entire area of the first Fresnel zone should be free of obstructions.

In practice, ensuring the purity of 60% of the 1st Fresnel zone guarantees minimal power loss.

Transmission of DVB-S2X/S2/S satellite signals in single-mode fiber. In the case of a fiber-optic bus, the size of the facility in which the system is implemented is irrelevant. The signal can be transmitted over hundreds of meters or even tens of kilometers without regeneration. For large buildings, this will greatly simplify the backbone of the system. A conventional system, based on copper wires, allows the signal to be transmitted in the trunk line for several tens of meters. This distance can be increased through the use of amplifiers, although this too has some limitations (as well as implementation and operating costs)...>>>more