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

An enzyme that will improve the quality of recycling.

The whole world has been trying for years to find a method for low-cost processing of plastic. Typical plastic, e.g. a bottle, turns into a ‘new’ material when recycled. Unfortunately, its quality and strength are inferior to the original. Scientists have engineered an enzyme that will help transform 90% of PET bottles into high quality material. The process takes only hours.

The leaf-branch compost cutinase (LCC) enzyme breaks down wax protective coating on plant leaves and, as demonstrated in studies, it also works on PET. However, the enzyme is no longer active at 65°C when PET begins to soften. French scientists from the University of Toulouse analyzed the enzyme structure while seeking ways to increase its resistance to high temperatures.

Polyethylene terephthalate (PET) is one of the most common plastics used globally.
The French scientists have found a way to process it with the aid of an enzyme.

The researchers introduced mutations into the enzyme to improve its ability to break down the PET material. More importantly, the enzyme is resistant to higher temperatures and remains stable at up to 72°C. It is 10,000 times more effective in breaking down PET bonds than the original LLC. During tests, the mutated enzyme proved to be effective by being able to break down 200 grams of PET within 10 hours. Chemical composites created that way were used to produce new plastic, which, as it turned out, remained a high quality material. The studies demonstrate that a potential exists for real biological recycling of PET on an industrial scale.

Hikvision - import/export of an NVR configuration file and an IP camera list file.

Hikvision NVRs allow for import and export of two configuration files, with the NVR settings and those of the connected IP cameras. The files can be exported directly from the NVR onto a USB memory device or to a PC, via a web browser. In the future, they can serve as a backup of the settings or speed up the process of installation and configuration of identical systems.

To save or import configuration files via a web browser:

Export/Import of configuration files (Hikvision DS-7608NI-I2 K22083 NVR)

Popular GSM antenna.

The Yagi-Uda or Yagi antenna is one of the most popular antenna designs. Despite a relatively simple design, it has a high gain, typically greater than 10 dBi. Such antennas can operate in the HF to UHF bands (3 MHz to 3 GHz), but often within a limited bandwidth around the center frequency of the Yagi antenna.

The basic geometry of a Yagi antenna is shown in the diagram below. The antenna has only a single active (driven) element, typically a half wave dipole or folded dipole. It means that only this member (W) of the structure is excited (fed/driven via a feed line from a generator). The rest of the components are parasitic elements which help to transmit the energy in a particular direction. The dipole is almost always the second element from the end, with a length to make it resonant at the center frequency (the required length of the dipole is somewhere between 0.45-0.48 of the wavelength).

One of the most popular Yagi-Uda antennas for GSM signal boosting is the 20-element ATK 20/800-980 MHz A7025 antenna with a built-in impedance transformer (balun). It is dedicated for example to A6765, A6775, A6785 GSM repeaters.

The 20-element ATK 20/800-980 MHz GSM antenna + 10 m cable + N plug A7028

What is the maximum range of TurboHD signal transmission?

In TurboHD systems, the video signal and power supply can be transmitted using coaxial cables or twisted pair cables. The transmission range depends on the cable type, required resolution and smoothness of the video. Exceeding a certain maximum results in a significant reduction in the image quality: loss of detail and blurring, and in the case of even longer distances, loss of synchronization and the image disappearance.

In the case of M75051 TurboHD 4.0 camera and an RG-59 cable,
the maximum transmission range is 700 meters

Measurements of DVB-T signals - modulation error ratio (MER).

The MER modulation error ratio is one of the basic digital signal parameters, which should be routinely measured. To put it simply, MER carries information on the level and type of noise that interferes with the digital signal (phase noise, amplitude noise etc.). MER can be treated not as an indicator of the signal quality, but as a measure of the distance of the received signal to the digital cliff. Without knowing this parameter, the antenna installer cannot guarantee stable reception in adverse weather conditions or other situations when the signal can fluctuate (e.g. interfered by a passing truck). Providing a safety margin through the MER measurement will avoid this situation. Typical and minimum values of the MER parameter for proper reception depend on modulation technique. For a 64-QAM modulation, they are 31 dB and 26 dB, respectively.

The Signal R10514 DVB-T/T2 meter can measure the MER parameter

To truly understand the importance of measuring the MER parameter, there is the need to explain the phenomenon of so-called digital cliff. In the case of a digital signal, the boundary between an ideal image quality and loss of reception is very sharp. In DVB-T, similarly to other digital broadcasting, we have to cope with this effect. The operation on the boundary is the reason that the picture appears to freeze up or show up like a mosaic. The recommended MER above 31 dB provides a large safety margin, practically eliminating the risk of accidental interruptions caused by various interference factors.

Two IP cameras on a pole, video transmission via optical fiber.

Extensive monitoring systems with cameras placed on poles require careful planning, including the choice of equipment necessary for signal transmission via optical fibers and for power supply. Due to limited space, installers have to minimize the number and size of the pieces of the additional equipment and the size of the protective enclosures.

In such cases, the ideal solution is to use the L11542 media converter with integrated 2-port switch. This way, there is no need for an additional switch and power supply. The number of connections is also limited to a minimum. The concept is presented in the diagram below.

The application of the L11542 Ethernet media converter with a built-in switch
for the transmission of signals from two IP cameras via single-mode fiber

Example of a 1U RACK distribution frame. Being able to handle a fusion splicer is no doubt essential when building fiber-optic systems. However, installers quickly realize that it is not the splicing alone that poses a problem....>>>more

An example of a simple RACK 1U distribution frame

TERRA dSCR multiswitches with auto gain control