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

Static negative capacitors can help create more energy-efficient computers.

Scientists from the US Department of Energy (DOE) together with colleagues from France and Russia created a permanent, static "negative capacitor", a device that 10 years ago was considered impossible to construct, because it would violate the laws of physics. Researchers have found that by connecting a "negative capacitor" with a "positive capacitor" in series, they can locally increase the voltage on the positive capacitor, obtaining a higher voltage than in the whole system. In this way, they can distribute electrical energy to regions of the circuit requiring a higher voltage, while the entire circuit is operating at a lower voltage.

In traditional capacitors, the voltage is proportional to the electric charge stored in them. Negative capacitors behave in a reverse way, an increased amount of charge reduces the voltage. Because negative capacitors are parts of larger structures, this phenomenon does not violate energy conservation.

Illustration of the domain wall motion (a-c and b-d) in the capacitor when adding a charge to one side (c).
The shift the domain wall due to a charge imbalance causes a negative capacitive effect.

The basic component of the negative capacitor presented by Valerii Vinokur and his colleagues is a filling made of a ferroelectric material, which is similar to a magnet, except that it has an internal electrical polarization, not a magnetic orientation. In a ferroelectric nanoparticle, a positive charge will be present on one surface and negative charges on the other, which creates electric fields that try to depolarize the material. By dividing the nanoparticle into two equal ferroelectric domains with opposite polarity, separated by a boundary called a domain wall, the scientists were able to minimize the effect of the total depolarization by the electric field. Then, by adding a charge to one of the ferroelectric domains, they moved the position of the domain wall between them. Due to the cylindrical nature of the nanoparticles, the domain wall began to shrink, moving to a new point of electrical equilibrium. And when the domain wall moves to one side due to the charge imbalance, some energy is released. This effect creates a static negative capacity.

As in everyday life computers are used by everyone on a daily basis, the energy necessary to run them becomes significant in the overall energy balance of the world. A research shows that the total electricity consumption of global data centers corresponds to 10 percent of all electricity consumed in the United States. A new physical phenomenon, such as negative capacity, can provide a new set of tools to improve the energetic efficiency of computers.

Single-cable multiswitch system.

Multiswitch systems with quatro LNBs receiving signals from two satellites (e.g. HotBird 13.0E and Astra 19.2E) have to use 8 coaxial cables (RG-6). A Wide Band LNB (e.g. A98222) has two outputs (H and V polarizations) and the distribution of signals from two satellites requires only four coaxial cables between the LNBs and the suitable multiswitch, reducing by half the number of the cables. With single local oscillators operating at 10.41 GHz, such LNBs provide much wider intermediate frequency band (290...2340 MHz) than conventional (legacy) LNBs.

The Wide-band LNB A98222 cooperates with Terra SRM-581 R80581 dSCR multiswitch that has 5 inputs. Two pairs of SAT IF inputs (V1, H1, V2, H2, 290...2340 MHz) should be connected to two Wide-band LNBs A98222, the fifth input (of active terrestrial path) is intended for DVB-T, DAB(+) and FM radio signals.

Installation company from Klodzko, Poland has deployed a multiswitch system based on TERRA SRM-581 R80581 multiswitches.

The SRM-581 R80581 cascadable multiswitch provides full support for receivers operating in two dynamic modes: SCR (Unicable I - 8 User Bands) and dSCR (Unicable II - 32 User Bands)

The SRM-581 R80581 multiswitch has the following inputs and outputs:

IP video intercom system.

The system shown below has been installed in a housing development with four single-family homes, all surrounded by a common fence, with access through one gateway. The video door phone system is based on the four-button gate/door station Hikvision DS-KV8402-IMDS-KV8402-IM G73635 and four 7" touch screen monitors DS-KH8300-T G74032. These components are powered with 24 VDC from 8-port PoE switch DS-KAD606-P G74814. Aside from the six PoE ports, the switch has two additional LAN ports that enable network and cascade connections. In the case of employing local power supplies, the installer could use a typical switch or router without PoE ports.
The system has been connected to the Internet via the TP-Link C6 N3255 router. The gate is controlled with the use of the Bira ES1-001 G74210 electric door strike with steel keeper/latch with 4 mm adjustment range. This model of electric strike can be energized with 12 VAC or VDC. In the system the supply voltage is provided by the G74321 power supply. The electric strike is controlled via a relay located in the gate station.

Block diagram and components of the IP video intercom system for 4 single-family homes

When someone presses a button of the gate/door station, the corresponding monitor in the selected apartment starts ringing. After receiving the call by the resident, two-way audio/video communication is established, and the resident can release the gate/door strike. In the absence of the resident(s) in the apartment, the call can be redirected to a smartphone, and its user may open the gate remotely.
The remote operation via an Android smartphone requires the installation of the Hik-Connect application. The configuration and operation from a PC is performed with the use of the iVMS-4200 client software.
The built-in 256 MB memory in each of the monitors allows for recording photos, messages, as well as for leaving information in the absence of residents. Additionally, the residents of each home can also freely communicate with residents in the other homes.

Protecting power supplies of electronic devices from overvoltages and interference (2).

Damage to a computer, television or stereo can occur as a result of overvoltage. It may end up with the replacement of a fuse and/ or varistor, but sometimes the damage affects the whole power supply. An effective protection against such situations is provided by the Acar 504WF RACK P1322 safety multi-outlet extension cord with surge suppressor.

Acar 504WF is a special version from the Acar 504 family of safety multi-outlet extension cords with surge suppressors. A highly efficient RFI filter built into the 504 WF model provides an important advantage in the case of powering audio-video devices, measurement systems, computers, communication equipment. The illuminated power switch indicates the presence of AC voltage in the protected outlets. The included hardware allows for mounting the power strip in a 19" RACK cabinet as a 2U module.

View of the ACAR 504WF RACK P1322 safety multi-outlet extension cord
with built-in surge suppressor and highly efficient RFI filter

The influence of F-number on the camera image.

The F-number of a camera lens refers to the maximum aperture (opening) of the diaphragm. The size of the aperture reflects the number given in the form f / x or Fx (x is the number of the aperture). So, the lower the F-number, the more light reaches the image senor, which means higher sensitivity of the camera.

CCTV cameras are usually equipped with F1.0, F1.4, or F2.0 lenses. F1.0 responds to the largest aperture, F1.4 – half of it, and F2.0 – four times smaller.

An F1.0 lens transmitting the maximum of the incident light is used in the Hikvision ColorVu series products that are the part of the TurboHD 5.0 offer. ColorVu cameras are extremely sensitive (0.0005 lx). Such high sensitivity ensures that the cameras generate useful images in light of low intensity, such as provided by street lamps or the moon.

So, why an F1.0 lens is not used in every CCTV camera? The production cost of the F1.0 lens is higher than of the most commonly used F1.4 versions. But that is not all – an important parameter of a cameras is the depth of field, which determines the range of distance in which the observed objects appear sharp. The higher the F-number, the smaller the aperture through which the light enters the camera and the greater the depth of field. When using ColorVu cameras, it is necessary to pay attention to the fact that the depth of field is slightly smaller.

Safe method of extracting optical fibers.

Among the types of fiber optic cables, a large group is that with single-tube or multi-tube construction. An example of a single-tube cable is the popular DRAKA U-DQ(ZN)BH universal cable. A common question asked by installers is the choice of suitable tools for terminating this type of cables.

The most important and indispensable tool is a rotary stripper, e.g. Ideal L5922. This type of tool can perform a number of functions, the most important of which is incision of the tube in which the fibers are placed. The incision is done by turning the blade several times on the surface of the tube. Then the tube can be broken by hand and the loose fragment taken out. This method guarantees 100% safety of the fibers inside the tube. Opening the tube with a regular upholsterer's knife or other type of a fiber stripper, or any different tool, does not give such a guarantee.

Rotary Coaxial Stripper IDEAL 45-163 L5922 is an indispensable installation tool

In addition to incising tubes, the L5922 stripper can be used to cut the outer sheath/jacket of other types of optical cables, both transversely (if we want to take off e.g. 30-50 cm of the sheath) and longitudinally (useful for cables not equipped with ripcord for tearing the sheath). All the blades are adjustable to control optimum cutting depth and to avoid damaging the internal structure of the cable.

Monitoring of an apartment building, based on Hikvision EasyIP 2.0plus cameras. The following figure shows a concept of a video monitoring system covering such a building, based on a Hikvision NVR and IP cameras from the EasyIP 2.0plus series. The outside area around the building is monitored by eight DS-2CD2043G0-I K17635 compact cameras with 4 MP resolution and 2.8 mm lens with 98° viewing angle. Inside the building there are four ceiling cameras DS-2CD2123G0-I K17321 with 2 MP resolution, equipped with 2.8 mm lenses with 114° viewing angle. Both models of the cameras have IR illuminators with range up to 30 m made in EXIR technology ensuring even lighting of the scene at night. The layout of the cameras allows for good identification of any potential vandals who might destroy the facade of the building.
The cameras are powered and connected to the NVR via the N29986 16-port PoE switch. The cameras of the EasyIP 2.0plus series support H265+, H.265, H.264+, H.264 video compression. With the use of two 3 TB hard drives, e.g. M89285, H.265 video compression and continuous recording mode at 25 fps for each camera, the data retention time is 15 days... >>>more

Schematic diagram of IP CCTV system based on Hikvision devices in an apartment building

Signal surge protection boxes