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

No. 39/2017 (Nov. 27, 2017)

A breakthrough in quantum communication.

Scientists at the Faculty of Physics at the University of Ottawa have successfully implemented quantum-encrypted transmission in field conditions.
Previously, experimenters have demonstrated in laboratories that a single light particle can encode multiple bits of information. But so far, such an experiment has never been conducted under natural conditions. Successful quantum communication experiments consisted in sending only one bit of information per photon (zero or one). The experiment in Ottawa has broken this limitation.
For example, a single letter was sent in the form of eight signals - combination of eight zeros/ones. It was very difficult to get successful results as the loss of any of the signals caused that the letter or even the whole message became unreadable. So, researchers have come to the conclusion that instead of sending multiple photons, it is better to limit the number of them by using high-dimensional quantum encryption, preserving all the information.
Scientists at the University of Ottawa have sent a message between two buildings using quantum cryptography
(source: www.livescience.com)
The method tested by the research team led by Ebrahim Karimi can reduce the number of photons needed to send a message by 50 percent. During the experiment, each photon encoded two bits of information, by taking advantage of both the spin and orbital angular momentum. The researchers demonstrated quantum encryption implemented in free-space optical network spanning two buildings 300 meters apart. They showed that the use of high-dimensional quantum encryption could enhance security by making the quantum channel more resistant to "noise" caused by atmospheric conditions or other external factors.
Researchers around the world focus on quantum cryptography as a way to increase security in the digital world. All messages, transactions and data exchanges between Internet users are encoded using complex mathematical algorithms. However, with the recent achievements in quantum computing, experts fear that mathematical algorithms will no longer be safe. Quantum computers, when they become reality, will be able to perform many calculations simultaneously. According to experts, quantum cryptography can be a response to the security concerns.

Transmission of DVB-T signals via optical fibers.

The line of TERRA transmodulators has been extended with a new model - mix-440 R81611. The transmodulator converts IP stream (TSoIP) provided in UDP/RTP protocols (unicast/multicast SPTS and MPTS transmissions) to four DVB-T COFDM multiplexes. The mix-440 R81611 panel receives IP stream with bit rate up to 200 Mbps and creates freely configurable four neighboring DVB-T multiplexes, each with maximum bit rate up to 31.66 Mbps (the limit is determined by the DVB-T standard).
Telecommunication operators can make fiber links up to 20 km long using the pairs of the devices:
  • IPTV streamer TERRA sti-440 (DVB-T/T2/C to IP, USB port) R81606, converting 4 DVB-T multiplexes to IP stream
  • IP to 4x DVB-T (COFDM) transmodulator TERRA mix-440 R81611, converting IP stream to DVB-T COFDM standard
and popular, cheap Ethernet media converters, e.g. L11025. The optical link(s) can be based on other single-mode or multimode converters or switches with SFP modules.
Professional VHF and UHF DVB-T Antenna Set (H/V): DIPOL 28/5-12/21-60DIN Rail Power Supply DR-60-12 (12VDC/4.5A, for Terra at/mt/ma modules)IPTV Streamer: TERRA sti-440 (DVB-T/T2/C to IP, USB port)Ethernet Media Converter M-203G (for two single-mode fibers up to 20km)Ethernet Media Converter M-203G (for two single-mode fibers up to 20km)IP to 4x DVB-T (COFDM) Transmodulator: TERRA mix-440 (100/1000Mbps, USB port)DIN Rail Power Supply DR-60-12 (12VDC/4.5A, for Terra at/mt/ma modules)
Example of an MATV system (DVB-T) with fiber-optic transmission medium
(transmission of four digital multiplexes via optical link up to 20 km)

Which antenna for LTE?

Currently, the fastest standard of data transmission in cellular networks is LTE (Long Term Evolution). In general, LTE mobile network technology can enable download speed up to 326 Mbps and upload speed up to 86 Mbps (with a channel width of 20 MHz, 64QAM and MIMO 4x4). LTE technology is flexible both in the terms of the frequency range and bandwidth of the transmission channel. LTE networks can operate in frequency bands from 700 MHz (non-urbanized areas - longer range) to 2.6 GHz (metropolitan areas - higher capacity). An important element of LTE is MIMO technology (Multiple Input Multiple Output) increasing transmission efficiency by employing multiple antennas on both ends of the transmission links.
LTE can operate over a wide frequency range. In Poland, the currently used frequency bands are 800 MHz, 1800 MHz and 2500 MHz. The next step will be 700 MHz band.
Information about the location of the nearest base station(s), transmission parameters (bands and technologies - GPRS, 3G, LTE) can usually be obtained from the customer service of the cellular operator. Aside from the antenna, usually it is necessary to buy the suitable adapter that fits the antenna input(s) of the modem/router and the original antenna connector(s).
When selecting an external antenna, the user of a modem should make sure whether the device supports MIMO technology (has two antenna connectors). If so, it is necessary to use an antenna that also supports this standard. It is a simple way to achieve the maximum throughput. The maximum distance from the base station should not exceed 6 kilometers.
ATK-LOG ALP LTE MIMO 2x2 Antenna (800-3000MHz, 10m cables, SMA plug)
The ATK-LOG ALP LTE MIMO 2x2 A7054_10 operates within 800-3000 MHz range,
and it comes with 10-meter cables terminated with SMA plugs.
The antenna has been designed for use with LTE modems (with two antenna connectors), cell phones, GSM, DCS, 3G modems.

Do not attempt mixing PC and APC connectors.

Despite several reasons why UPC and APC connectors should not be mixed (PC and APC connectors - are they exchangeable?), some installers employing devices with high power budgets do not pay attention to this issue. It may happen, however, that the excessive attenuation will not allow any transmission.
A simple test verifying the approximate value of the attenuation of such incorrect connection has been conducted. For this purpose there have been employed light source Grandway L5825 and optical power meter Grandway L5821. The measuring system was calibrated using two L3213 patch cords and L4211 adapter. Then, another L4211 adapter was added to connect in series the L3211 patch cord terminated on both ends with SC/PC connectors. The steps are shown in the following figures.
Calibration of the measuring system
Measurement of the attenuation of correct connection
Measurement of the attenuation of incorrect connection
Measurement of attenuation of SC PC/PC patch cord
The L5825 Grandway light source generates laser bream at a constant power level of -5 dBm. The measurements were made at a wavelength of 1310 nm. During calibration, the meter indicated signal level of -5.20 dBm. This value was the reference point for measuring the attenuation of patch cords. After plugging in the SC/PC - SC/PC patch cord with a length of one meter, the meter showed the result of -5.66 dBm. This meant that the measured attenuation of the patch cord was 0.46 dB.
Measurement of the attenuation of the incorrect connection with APC patch cord
After plugging in the L3222 SC/APC - SC/APC patchcord instead, the level measured by the meter dropped dramatically. The reading of -12.34 dBm meant that the attenuation of the connection was as high as 7.14 dB. In order to confirm the result, the measurement was repeated for another L3222 patch cord - the reading was very similar. The high attenuation is caused by air gaps between the ferrule end faces of the PC and APC connectors, strongly attenuating the transmitted signal. Due to very high reflectance of the connections, a significant portion of the signal is reflected back to the transmitter, and only a small part of it is transmitted further. With the measurement based on transmission method, the reflected signal returning to the light source does not cause any harm.
The accuracy of the L5821 optical power meter is +/- 0.35 dB. In the case of the measurement of the attenuation of the proper patch cord, the possible error was comparable with the measured value, however the purpose of the tests was rather not to obtain absolute values, but compare the results for both cases. It is clearly visible that the difference in attenuation between the application of SC/PC and SC/APC patch cords with the same length is immense, and the error margin can be neglected.

Codec optimized for video surveillance systems: H.265+.

H.265+ is the latest video compression method implemented in Hikvision devices. The method is based on adaptive image encoding with excellent performance while maintaining high image quality. On average, the generated data is twice as low as in the case of H.265 standard. The result has been achieved by the use of special techniques:
  • motion prediction: different encoding used for moving objects isolated from a static background;
  • decrease of encoding noise: the background is encoded with other parameters than the moving objects, which reduces noise and bitrate;
  • long-term planning of the bitrate: the codec "learns" the monitored scene and adjusts the instantaneous coding parameters to the current changes in the image - in the case of highly dynamic scenes, the momentary bitrate increases significantly (the bit rate of H.265+ encoding is given as an average value, not a maximum, so the temporary fluctuations can be very large).
Bit rate in H.265 and H.265+
In the case of H.265+, the optimization concerns the average value in a longer period of time

ANR function in Hikvision systems.

The video from an IP camera is transmitted to the IP NVR in the form of data stream. In the case of a network failure or bandwidth reduction, the information is irretrievably lost, because the network does not buffer packets and the camera cannot send them again. This is the reason for the increasing popularity of IP cameras with SD/SDHC card recording option. The ANR (Automatic Network Replenishment) solution developed by Hikvision limits the recording on the card placed in the dedicated camera only to the periods of problems with connectivity between the camera and NVR. After the end of the failure, the emergency recordings are automatically transferred to the NVR. So, in the event of interruptions in the transmission, the operator of the system does not need to take any actions to complete the video footage. The function is available in IP NVRs from the K and I series. They have to cooperate with Hikvision IP cameras equipped with memory card slot (marked with F letter in type designation) and suitable microSD card.
Memory Card: microSDXC 64GB UHS-I class 10 (with SD adapter)4K IP NVR: Hikvision DS-7608NI-I2 (8ch, 80Mbps, 2xSATA, Alarm IN/OUT, VGA, HDMI)Ceiling IP Camera: Hikvision DS-2CD2125FWD-I (2MP, 2.8mm, 0.005 lx, IR up to 30m, WDR, IK10, H.265/H.264)
The idea of ANR function

New products offered by DIPOL

LNB Mount (for Triax dishes)
LNB Mount (for Triax dishes) A9896 is used for mounting LNB in a range of Triax satellite dishes.

Antenna Box for DIPOL Antennas
Antenna Box for DIPOL Antennas E9315 is used for DIPOL antennas. It can protect a balun or amplifier placed inside.

4K IP NVR: Hikvision DS-7716NI-K4 (16ch, 160Mbps, 4xSATA, Alarm IN/OUT, VGA, HDMI, H.265/H.264)
4K IP NVR Hikvision DS-7716NI-K4 K22167 Hikvision DS-7716NI-K4 is a modern 16-channel IP network video recorder capable of monitoring, recording and playing back images from 16 IP cameras of megapixel resolutions, up to 8 MP. Its independent HDMI (up to 4K) and VGA (up to 1080p) monitor outputs can provide images with different layouts.

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