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DIPOL Weekly Review - TV and SAT TV, CCTV, WLAN
No. 31/2016 (Oct. 3, 2016)
Computers increasingly better understand speech. Microsoft announced a new record in speech recognition systems. During a standard test of their system, they achieved error rate of 6.3%, the lowest value in history. This way they defeated a team from IBM, which recently boasted a result of 6.6%. These results are impressive, especially that people taking such tests mistakenly recognize 4% of the words.
The rapid development of voice recognition systems occurred only in recent years. In 1995, the minimum error rate was 43%, in 2014 - 15.2%. A decrease of the error rate to values below 10% was possible with the use of neural networks. Microsoft managed to create faster algorithms for speech recognition based on the open source Microsoft Computational Network Toolkit (CNTK).
Optimized algorithms, along with the technique of parallel processing using GPUs, contributed to the achievement of the record result. Scientists say that the systems will be further improved and come closer to the results of humans. The improved quality of speech recognition will increase the comfort of using the Cortana intelligent personal assistant and on-the-fly translations in Skype.
The competing IBM Watson has reached 6.6% error rate in speech recognition
Microsoft and other competing big companies (IBM, Google, Apple, Amazon) create better and better systems to interact with people. The current trend is to implement such systems in modern solutions for wearable electronics, smart homes, vehicles and other equipment. The motto guiding developers is to build devices that can anticipate and meet user expectations by understanding speech, without having to be restricted to predefined commands. Advanced speech recognition is one of the key issues in Microsoft's vision of constructing devices that can "see, hear, speak and even understand".
0 dB effect in single frequency networks (SFN). In many places where signals from the main (high-power) DVB-T transmitter are insufficient and do not guarantee a satisfactory reception quality, it is necessary to use auxiliary transmitters - in the case of SFN these are low power co-channel repeaters used as gap fillers for all or selected digital multiplexes. The consequence of the additional sources of signals may be a significant difference between signal levels of the received multiplexes, especially in the latter case. The differences can cause reception problems when the antennas or antenna systems have high gain, and the antenna amplifiers and/or the receivers are overdriven, which causes signal distortion.
Another significant problem that occurs in SFN solutions is called "0 dB effect." This phenomenon is particularly noticeable in the case of receivers using less sophisticated signal processing systems and when the signals received on the same channel have good, comparable ("0 dB") levels and very small time differences. The problem consists in inability of the receiver to synchronize with such signals and, consequently, in distorted or no reception. The symptoms of such a situation are often large fluctuations of signal quality level displayed by the receiver. The "0 dB effect" is especially noticeable in the cases where:
  • the receiving DVB-T antenna, the low-power and high-power transmitters are located in the same line
  • the receiving DVB-T antenna has a wide horizontal reception angle and the both transmitters are located within this angle
Transmission of HDMI signal over coaxial cable. RF over coax HDMI converters/extenders allow for transmission of HDMI signals over long distances via 75 ohm coaxial cables. In order to provide the HDMI signal to several TVs/monitors, the output signal from the transmitter can be split by a typical TV splitter. Each of the paths has to be terminated with the dedicated receiver. In the case of short transmission path(s), it may be necessary to use suitable attenuator(s).
To establish the connection between the transmitter and receiver, the user must select the same channel in both units (there is a choice among 100 TV channels). The width of the channel is 7 or 8 MHz (depending on the channel number). The selected channel can be injected into an existing antenna system, on the condition that it ensures necessary spacing to other channels used in the system.
HDMI Extender (RF over coax)HDMI Extender (RF over coax)3-Way TV/FM Splitter R-3 Signal
H264+ compression in Turbo 3.0 DVRs. Turbo HD 3.0 DVRs can record surveillance video with the use of advanced and very efficient H.264+ compression. The image quality is identical to that obtained by the standard H.264 codec, however the resultant bit rates and consequently the sizes of the data files can be substantially reduced (typically ca. 50%).
A comparison of the bit rates (Mbps) in H.264+ and H.264 video coding systems for a range of image resolutions
The H.264 + encoding method is suited to video monitoring systems. The method is characterized by a very high level of compression, especially in the case of comparatively static scenes, prevailing in most video surveillance systems (with no motion in the scene the bit rate is close to 0). Thanks to the reduced amount of data, the demand for storage space is significantly lower. The use of the compression method ensures real savings, for example one can choose a DVR model supporting two hard drives instead of a more expensive model with place for four disks.
Checking the continuity of fiber optic cable using a reflectometer. The stage of laying cables is always one of the most time-consuming, and thus costly phases of each installation. In the case of fiber optic cables, they can be easily damaged by incorrect transport or storage (microbending), so it is particularly important to check them before installation in cable ducts, jointing chambers, walls, etc.
Theoretically, a cable can be checked using a light source and power meter, but usually it is difficult to implement this method because of the lack of access to the other end of the cable wound on the drum. In such a situation the proper technique is to use a reflectometer. It is enough to weld a pigtail to the free end of the cable and connect the reflectometer. Due to the fact that there is a certain event dead zone (the minimum distance after which a reflection can be detected by the reflectometer), the first several or so meters of the cable could not be verified. For this reason one should connect in series an additional cable run with the necessary length.
The whole process of checking the cable on the drum takes a few minutes and allows the installer to avoid the disastrous deployment of a damaged cable. The following figure shows an example of reflectometric measurement of a 500-meter section of optical fiber wound on a drum. This cable was probably damaged at the stage of production.
Verification of fiber optic cable on a drum with the use of Grandway FHO3000-D26 L5828 optical time-domain reflectometer. Visible big damage around 348 meter. The application of the cable in an optical link would probably result in the necessity of its replacement.
Integration of CCTV/IP CCTV and alarm systems. A CCTV or IP CCTV system can be integrated with an alarm system with the use of alarm inputs and outputs. Hikvision IP cameras from the budget series (DS-2CD2XXXX-X) can trigger recording on the NVR in the case of events like motion detection, crossing virtual line, or intrusion of an area. Each event can be correlated with an alarm output of the NVR, which can be connected to the control panel of an alarm system. If the alarm system is equipped with a notification module, it can alert users about the occurrence of an event e.g. in the form of SMSes. The integration of the systems can also be organized in the opposite way, by connecting the alarm outputs of the alarm control panel to the alarm inputs of the NVR. The recording is still activated by the motion detection, crossing virtual line, or intrusion of an area, but any alarm signal from the control panel triggers continuous recording from all cameras in the system. With this configuration, the system normally saves the hard disk space, but in the case of activation of the alarm system guarantees a full coverage of the emergency situation.
Relay Module ROPAM RM85-12V-1PTouch Panel ROPAM TPR-2WSurface-mount Installation Box AWO205 17/TRP40/SATELCompact IP Camera: Hikvision DS-2CD2022WD-I (2MP, 4mm, 0.01 lx, IR up to 30m)PoE Switch: ULTIPOWER 0288af (8xRJ45/PoE-802.3af, RJ45-GbE, 2xSFP-GbE)IP NVR Hikvision DS-7608NI-E2/A (8ch, 50Mbps, 2xSATA, VGA, HDMI, ALARM IN/OUT)Input Expander ROPAM EXP-I8Rechargeable Battery MWS 7.2-12 (12V, 7.2Ah)Alarm Control Panel ROPAM NeoGSM-PS (main board)GSM Antenna ROPAM AT-GSM-MINI
Integration of IP CCTV and alarm system in a one-family house
New products
Installation Box for Compact Cameras: PFA134
Installation Box for Compact Cameras PFA134 M5714 has been designed for Hikvision compact cameras, i.e. M7551, M7552, M7553, M7556, M7562, M7563, M7566, M7567, M7569, K17638, K1777. The space inside the box is sufficient for hiding cable connections. The box is made of aluminum.
Single-mode Patch Cord ULTIMODE PC-523 (1m, G.652D, SC/APC-FC/APC)
Single-mode Patch Cord ULTIMODE PC-523 L3223 is a section of fiber optic cable with a length of 1 meter, terminated on one end with SC/APC connector, and on the other end with FC/APC connector.
Anchoring Clamp TELENCO DROP 3-6 mm
Anchoring Clamp TELENCO DROP 3-6 mm E8575 allows the suspension of a cable including a short reserve of it. The entire clamp is coated with a UV protective layer. The clamp is designed for cables with a diameter between 3 and 6 mm.
September 26, 2016 - over 10 thousand subscribers of the biweekly Special Offers Info. The latest Special Offers Info in Polish got through to over 10,000 subscribers, and in other languages to 2,000 subscribers. Every two weeks the subscribers receive into their email inboxes information about the current promotions with individual special prices. This is the key to the best prices currently available. To be covered by the program of price promotions, you should simply register at DIPOL e-Store and agree to receive the electronic information. We invite you to try!
The Special Offers Info has been issued since November 22, 2013.
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