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

What is the limit of transistor miniaturization?

A team of researchers from China's Tsinghua University in Beijing has developed the world's smallest MOSFET transistor structure. The record-small 0.34 nm gate was made possible by using an atom-thin sheet of graphene as the gate of the transistor.

Transistors are basic elements used in the construction of integrated circuits. They have three leads: source (where the electric current enters the transistor), drain (the point where the electric current leaves the transistor) and gate (controls the flow of current). The gate length is the most important parameter that determines the size of the circuit. Today's transistors are based on silicon, but with miniaturization quantum tunnelling has became a problem seen as electron skipping and malfunction of the circuit. The researchers have therefore used molybdenum disulfide (MoS2), another semiconductor material. This resulted in an extremely thin atom-thin structure. The source and drain electrodes are strips of metal in contact with molybdenum disulfide, while the gate has been built using a sheet of graphene. It has been arranged in such a way that the one-atom structure is responsible for the current flow. When the gate is in the powered state its width is only 0.34 nm which is the same as that of the graphene layer. To get an idea of the size we are talking about: the diameter of a human hair is between 80,000 and 100,000 nanometers.

The transistor itself is so simple that it is not actually able to do any useful work, but already large assemblies of transistors make it possible to perform various mathematical operations. For example, today's processors are composed of billions of transistors. The development of computers is determined by increasing their speed, which in turn is related to increasing the number of transistors. Reducing the size of the transistor allows us to build even faster and more energy efficient computers. However, it is a long way from demonstrating a working transistor to using it in a real product.

Why is calibration of fiber optic splicers important?

Calibrating a fiber optic splicer involves adjusting the power and temperature of the generated arc to the current environmental conditions. A properly adjusted arc allows for proper splices to be made, both in terms of attenuation and strength. Therefore, calibration should always be performed before the actual splicing – at the beginning of work or in the case of drastically changing conditions (e.g. a sudden drop in temperature resulting from splicing inside a building and further work outside).

The most expensive splicer models are equipped with pressure and temperature sensors that allow automatic calibration in real time. Most popular machines, however, require a manual calibration that takes a few minutes. Failure to calibrate will not always result in a bad splice. However, there is a risk that the splices will be correct from the attenuation point of view, but due to insufficient splicing temperature they will break after some time – cases of splices breaking after only an hour are known.

The Signal Fire AI-9 L5875 fiber optic splicer is based on popular calibration method – the fibers placed in the welding compartment are subjected to successive electric arcs. The fibers are fused and the splicing software measures and analyzes the distance over which the fiber ends retract. Based on the measurement, the appropriate arc parameters are determined.

The calibration of Signal Fire is done by selecting "Arc Calibration" option in the management application. When the fibers are inserted into the splicing chamber and the cover is closed, the calibration process starts automatically. When finished, the splicer switches to normal mode, i.e. is prepared for regular splicing operations.

In the winter period, installers should pay particular attention to the proper preparation of the splicing equipment before commencing work. A splicer that has spent the night in a car parked outside and has just been brought into a room with room temperature is not ready for immediate use: the fogged camera lens may result in erroneous fiber positioning and auto-focus problems. To avoid such issues, installers should make sure splicers are stored in appropriate temperature conditions.

Design of a fiber optic RF/SAT system.

DIPOL offers the MR-9xx and MV-9xx TERRA mustiswitches for multi-family buildings, designed in accordance with the requirements of TV/SAT systems, ensuring signal reception from two satellites. The solution offered is quite popular, among others on the Polish, British, German and Australian markets. Advanced TERRA multiswitches have been a still highly recognized a solution for large SMATV systems in Poland since 2004. Quality built, stability of parameters and very low failure rate make these multiswitches a product of choice to even the most demanding customers. DIPOL has been selling TERRA products since 1996. The product warranty extended to 4 years has been on offer from March 2013.

Below, a diagram of an exemplary SMATV system of a multi-family building is shown. It has been saved in various formats: dwg, pdf and stn (SatNet system design software file) and can be easily adapted to your own requirements in any form.

///The RF/SAT diagram shows an example of a SMATV optical-copper multiswitch system for two satellites. Satellite and terrestrial TV signals were supplied via coaxial cables to the optical transmitter OT501W A9872. Then, optical fiber cabling (1 fiber per 1 optical transmitter) replaced the typical 9-wire multiswitch bus. This solution can be used in large buildings with the distances between the staircases are more than several dozen meters or when the multiswitches and subscriber devices require protection against possible overvoltages caused by lightning in the vicinity of the antenna. The OR501W A9877 optical receivers perform reverse conversion of the medium. Downstream the optical receivers, there are MV-932L R70832 multiswitches located, where the subscriber cabling begins.

Conductor layout in RJ-45 connectors.

In computer networks 8P8C eight-pin modular connectors (popular, but incorrect name - RJ-45) are commonly used.

T568A and T568B termination (pinout) for 100Base-T networks:

• T568B (more popular)
• T568A

If the two sides of the cable are terminated in the same way, it will be a straight-through cable, often called a patch cable. Otherwise, it will be a crossover cable.
Straight-through cables are used to connect computers/peripherals to networking devices such as hubs and switches, while crossover cables are usually used to create a direct connection between two computers.

Enabling rules in Hikvision IP cameras.

When configuring basic events (e.g. motion detection) or intelligent events (e.g. virtual line, intrusion area) it is helpful to enable rules in the camera. This way the moving objects and set rules are visible in the image, which makes the whole configuration easier. For example, the drawn virtual line is marked in blue, and the moving objects in green. When an object meets the criterion of crossing the line, both the virtual line and the object marking turns red. To enable rules display, after logging in to a camera, go to the Configuration -> Local tab.

Control of PTZ cameras with an USB control unit.

For PTZ cameras, it is possible to remotely control the position of the camera and its optical zooming in. This means that the operator can aim the camera at any point and zoom it in. The control is possible directly from the DVR or remotely via a browser or client applications– both for a PC and phone. If the operator needs to move the camera frequently, the most convenient way is to control it using a control panel.

The simplest control unit, the DS-1005KI M77921, connects with the DVR via USB interface. The first step in the configuration is switching on USB manipulator mode on the panel (two LEDs are on). After connecting to the DVR, it is possible to control the cameras. Just select the number of the camera you want to control on the numeric keypad and press the left button of the joystick – this activates the PTZ control. The camera can be controlled by moving the joystick in the same direction and turning the knob to zoom in or out. The panel can also be connected to a computer where the control of the cameras is performed by client software. In that case, activate the operator keyboard mode – one control LED will lit.

4K HDMI transmission over UTP cable. Signal 4K60 HDMI to UTP converter with USB ipcolor H3643 enables transmission of HDMI signal over long distances using category 6 or higher UTP cable. The device transmits a lossless image supporting HDMI 2.0, HDR (18 Gbps band), DTS. Additionally it has an integrated USB extension cable... >>>more