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

Innovative approach to optical semantic communication.

A team of scientists led by Prof. Ming Tang and Dr. Hao Wu from Huazhong University of Science and Technology in China, in collaboration with doctoral students Zheng Gao and Ting Jiang, has developed an innovative optical semantic communication system using multimode fiber (MMF). The new method significantly improves both, the bandwidth and the transmission resistance to interference. The researchers emphasized that they applied multidimensional semantic coding and decoding in the frequency domain, using intermodal dispersion in multimode fiber (MMF). By mapping symbols to different frequencies, a sevenfold increase in bandwidth was achieved compared to traditional coding methods. In addition, the introduction of PAM-4 (Pulse Amplitude Modulation with 4 amplitude levels) technology contributed to a significant increase in the spectral efficiency of the system. This has allowed for a transmission speed of 9.12 bps/Hz while maintaining zero decoding errors.

PAM-4 technology is an advanced signal modulation technique that increases the amount of information transmitted without the need to expand the bandwidth. In traditional systems, such as PAM-2, the signal only takes on two voltage levels: low (0) and high (1). In PAM-4, four levels are used instead of two, which allows for the coding of two bits of information in one time unit instead of one.

Semantic communication is an innovative approach to information transmission that focuses on conveying meaning instead of raw data. Unlike traditional methods, where data is sent bit by bit, semantic communication analyzes the content, filters out the relevant elements, and compresses the information in a way that maximizes transmission efficiency. This process involves several key stages. First, the data is interpreted in terms of its meaning, for example in the case of text, image or sound. Then the system transforms it into a more efficient representation, often using artificial intelligence for coding and compression. Once encoded, the information is sent through a communication channel, such as a fiber optic network. Finally, the recipient decodes and reconstructs the content, recreating its original meaning and, if necessary, filling in missing elements based on the context.

According to the researchers, the new method of semantic communication using multimode optical fibers represents a significant step forward in the field of optical transmission. The possibility of directly transmitting semantic information via optical frequencies, combined with the high capacity and resilience of the system, makes this solution extremely promising for future communication technologies.

Mobile camera mounted on the windshield.

The Protect C420 M80420 mobile camera is an advanced vehicle monitoring solution that combines two 1080p AHD cameras in a single compact housing. One of the key advantages of the device is the mounting bracket that ensures easy and stable system installation.

The camera is mounted on the vehicle windshield with adhesive tape, which eliminates the need for drilling and complicated installation. The bracket has two joints that allow the angle to be adjusted precisely to the shape of the windshield and the cameras to be positioned optimally. The front camera can be adjusted vertically and locked in place with two screws. This allows the lenses to be perfectly aligned with the road ahead and the interior of the cab.

In addition, the front camera can be adjusted vertically and locked in place with two screws. This solution prevents accidental changes to the camera settings, ensuring a stable image even during intense vehicle operation.
The device has 2 video outputs (an adapter from M12 6 pins to 2 x M12 4 pins is included), so it can be connected to 2 channels of the recorder. The camera is compatible with Protect. recorders.

Modular headend as a signal source in a coaxial system.

Headends distributing satellite programs after conversion to DVB-T COFDM digital form are a popular solution used in many hotels. Satellite channels can be an addition to the terrestrial television programs or be the only part of the package offered. There are many benefits of using them:

Digital Terra headend can be used in a wide range of hotels and other facilities with different number of rooms, including the largest ones. It is easy to extend the programming by adding next modules. Thanks to the conversion of DVB-S/S2 signals into DVB-T COFDM standard, the satellite programming can be received by regular televisions, similarly to normal DVB-T broadcasts. Both the terrestrial DVB-T broadcasts and converted satellite channels can be easily distributed to the outlets via typical TV installations based on coaxial cabling.

The photo above shows an example of the installation of the TERRA head-end station to the CD001 housing with the BD001 R90001 DIN rail. Additionally, on the mounting plate ID001 R90003, there are the SRM-522 R80522 multiswitch and Ethernet switch mounted. The whole system has the fan panel with a thermostat FD001 R90002 added. The modular and versatile design of the TERRA headend allows for the system of any modules (transmodulators) on the BD001 R90001 DIN rail. The following table shows the specifications of the individual TERRA transmodulators.

Changing the call forwarding time in Hikvision IP video intercom monitors.

In the Hikvision IP video door entry system, it is possible to forward the call of the caller from the external door station, directly to the application installed on the smartphone. To do this, you need to create a Hik-Connect account, add a video door station to your account, install the Hik-Connect app on your smartphone and log in to your account. Add the video intercom monitor to the account, through which the connection with the door station will be made (if you have a Villa-type single-subscriber station, it is possible to add the door station itself to the Hik-Connect cloud directly). Once the Hik-Connect service is enabled and properly configured, pressing the call button on the door station will trigger a call on both the monitor and the smartphone with the app installed. By default, the call forwarding time on the monitor is set to "0 s", which means that if you press the call button on the door station, the monitor and the smartphone app will ring at the same time. If this time is changed, for example, to "10 s", if the tenant does not answer the call within 10 s, only then will the call be forwarded to the app. To change this time from the iVMS-4200 level, after entering the door station settings, go to the tab: Intercom -> Time Parameters -> Call Forwarding time.

Measurements of the attenuation of splices made with the Sendun SD-9+.

The Sendun SD-9+ L5877 fiber optic splicer is a model the production of which began in the second half of 2023. After nearly two years on the market, the model has gained recognition among a wide range of installers working in various areas of FTTH networks and low-current systems using fiber optic cabling.

Take a look at the video prepared by Dipol's team of engineers, presenting the Sendun SD-9+ splicer's capabilities in splicing single-mode optical fibers in G.652.D, G.657.A1 and G.657.A2 standards. Splice attenuation was verified in a two-way OTDR measurement made with a high-end EXFO brand OTDR.

The measurements showed that the splicer performs splices with good parameters, also when splicing fibers of different standards. When splicing G.652.D fibers, the average splice attenuation for 1310 nm was 0.06 dB, for the G.652.D – G.657.A1 splice it was 0.03 dB, while for the G.652.D – G.657.A2 splice it was 0.08 dB. During the 12 measurements, the worst recorded result was 0.12 dB, when combining fibers with extremely different mod field diameters. These results showed that the splicer can be successfully used in various installation scenarios.

In addition, the fiber image imaged by the 380x magnification optics and CMOS transducer allows accurate analysis of any anomalies occurring during splicing. This allows a preliminary assessment of the splice, right after it is made.

The video is intended for those interested in purchasing a fiber optic splicer, as well as those who already have a splicer. A high level of educational value of the video has been taken care of, so those interested in any of the issues:

are sure to find something of interest in it.

Industrial switches.

Industrial switches are designed for installation in demanding industrial environments, where they may be exposed to factors such as high levels of dust, extreme temperatures or high humidity. It is also recommended to install them in systems placed on poles or in telecommunications manholes, using sealed enclosures.

Ultipower switches offer Ethernet ports (Fast Ethernet or Gigabit Ethernet, depending on the model), enabling the connection of devices such as IP cameras or computers. The housing complies with the IP40 standard, providing protection against solid objects with a diameter greater than 1 mm and access to hazardous parts.

All ports support PoE power, provided that the switch is powered by 48 V DC. In addition, the devices are equipped with an SFP port which allows the conversion of the transmission medium to optical fiber.

The devices also have the following additional functions:

• Extended function enabling power supply to devices connected with a twisted pair cable up to 250 m long
• PoE Auto Check function automatically performs a current restart of the connected device in case it is suspended
• HiPoE 90W support for ports 1 and 2 (N299704 switch only)
• PD function allows the switch to be powered via the Ethernet port (N299707 switch only)

In the example shown, the switches are installed in sealed housings on the poles. IP cameras are connected to the switch and powered by PoE (48 V, 802.3af). A single-mode fiber optic cable with LC connectors and SFP inserts was routed between the poles to create a network of five cameras and an NVR. The use of industrial switches significantly increases the reliability of the system because they are more resistant to voltage surges and difficult weather conditions. In addition, the optical fiber used between the poles effectively electrically insulates the two locations of the camera points, increasing the stability and security of the network.

Static color palette for thermal imaging cameras. Thermal imaging cameras record infrared radiation emitted by objects and convert it into an image in which the intensity of the radiation corresponds to specific temperature levels. The use of image coloring improves image clarity and makes it easier to analyze, as different temperatures are easier to identify with assigned colors...>>>more