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No. 16/2013 (April 15, 2013)
Terabit level graphene antennas.
Researches from Georgia Institute of Technology developed plans for an unusual antennas made of graphene - a material which is the leading candidate for replacing silicon in integrated circuits. Such antennas made of the "material of the future" will be capable of data transfer speeds of 1 Tbps at a distance of 1 m, and theoretically even up to 100 Tbps at distances not exceeding a few centimeters.
The hardware architecture of a device
for terabit wireless communication
(source: gatech.edu)
for terabit wireless communication
(source: gatech.edu)
The proposed graphene antenna must be formed as narrow strips having a width of 10 to 100 nanometers and length of one micrometer. This will allow wireless transmission and reception of data in the terahertz frequency range. So, the graphene antennas will be extremely small. They could be seamlessly integrated e.g. in mobile phones to transfer information between their components and for short-range high-speed communication with other devices.
To use the advantages of the antennas is not enough to embed them in various devices. It is also necessary to create other nano-devices that would be able to process and store enormous data collections.
The structure of graphene, with atoms arranged in a regular hexagonal pattern
(source: wikipedia.org)
(source: wikipedia.org)
Graphene is one of the allotropic forms of carbon. In 2010, Andre Geim and Konstantin Novoselov received the Nobel Prize in Physics "for groundbreaking experiments regarding the two-dimensional material graphene". In March 2011, the Institute of Electronic Materials Technology and Department of Physics, Warsaw University, announced information about joint development of technology enabling production on an industrial scale of large pieces of material called Grafen (Graphene), patented later that year.
The material consists of a single layer of carbon atoms arranged in a honeycomb crystal lattice. The properties of graphene include very good thermal and electrical conductivity, optical transparency (it absorbs only 2.3% of visible light), flexibility and 100-times greater strength than steel.
Graphene is a material of the future. The European Commission has recognized the study of graphene as a strategic program of the UE and will spend on it one billion euros.
The material consists of a single layer of carbon atoms arranged in a honeycomb crystal lattice. The properties of graphene include very good thermal and electrical conductivity, optical transparency (it absorbs only 2.3% of visible light), flexibility and 100-times greater strength than steel.
Graphene is a material of the future. The European Commission has recognized the study of graphene as a strategic program of the UE and will spend on it one billion euros.
IP CCTV system using two pairs of M-407M-2 L11542 media converters
DIPOL offers sets of two Ethernet media converters Ultimode M-407M-2 L11542, one of the units is equipped with two-port switch that can be used e.g. for connecting two IP cameras. Each unit has one SC connector used to transmit (Tx) or receive (Rx) optical signals. It is possible due to the use of wavelength-division multiplexing technology (WDM) - different wavelengths of laser beam carry different signals, over one strand of fiber. It significantly lowers installation costs.
The cost of cabling or its lease is often the decisive factor in choosing the right solution for a specific application. Additionally, the installer has to secure the necessary conditions for any equipment installed outdoors (operating temperature and humidity). The optimum solution in the example shown in the diagram has been to use two sets of L11542 media converters and two optical fibers.
How many SD/HD channels can be combined into one DVB-T multiplex created in a headend?
One of the modules for the TERRA MMH-3000 headend is TDX-311C R81711C - 8PSK/QPSK CI receiver and DVB-T modulator. It converts DVB-S/S2 satellite channels from one transponder (encrypted or not) into digital DVB-T multiplex (COFDM).
An example of a table from the DigitalBitrate service with data concerning selected Hotbird 13.0E transponder (11393V) - channel names, PIDs, bitrates etc.
(click on to enlarge)
(click on to enlarge)
Summary statistics for the 11393V transponder
In the example, the total bitrate of the 11393V transponder from Hotbird 13.0E is about 42 Mbps (31.6 Mbps - video streams, 5.4 Mbps - audio streams). Currently, the transponder provides 18 services (channels). The average video bitrates of the five most popular channels are: 4.0 Mbps (TVN), 3.4 Mbps (TVN24), 2.6 Mbps (TVN7), 3.2 Mbps (TVN Turbo and TVN Style). So, the video and audio streams should take about 16.4 Mbps. The web service also provides maximum bitrates occurring during a day. In this case, the total value of the bitrate could amount to 24.4 Mbps. However, the situation in which all the channels have maximum data rates at the same moment is practically impossible.
The maximum bitrate at the output of TDX-311C R81711C DVB-T modulator depends on the modulation scheme, RF channel bandwidth, Guard Interval and FEC parameters. In the case of QAM64 modulation scheme, 8 MHz channel width, Guard Interval of 1/32 and FEC 7/8, it is 31.66 Mbps. It is not recommended to make use of the maximum bitrate. In the case of distributing satellite TV channels, the safety margin should be 10-15% of the maximum capacity. In systems with very old cabling, it may be necessary to increase Guard Interval parameter, which will somewhat decrease the maximum output bitrate, as well.
Focusing problems in "box" cameras.
It sometimes happens that we can't achieve clear image during the adjustment of lens sharpness - it appears mainly in varifocal lenses, especially for extreme focal lengths. In this case we should loosen the screw which is used to block a special ring on the camera front (with the wrench included with almost every camera). With the ring we should adjust the best possible image sharpness - back focus. The adjustment should be made at the shortest focal length and sharpness set at infinity. Such sharpness adjustment should be made with fully opened iris, using e.g. gray filter (it will ensure proper focus also in night conditions).
In Sunell box cameras the distance between the image sensor and a lens
is adjustable by turning the ring secured by screw available from the bottom of the camera
is adjustable by turning the ring secured by screw available from the bottom of the camera
The self-diagnostics includes the following situations:
- HDD Full
- HDD Error
- Network Disconnected - no connection with LAN
- IP Conflicted - a duplicated IP address
- Illegal Login - invalid username or password
- Abnormal Video Signal
- Input / Output Video Standard Mismatch
- Record Exception - no space for recording e.g. onto an external storage device
- Motion - motion detection in one of the four detection zones defined for each camera
- Tamper - proof - camera tampering, blockade etc.
- Video loss
View of the Hikvision configuration window (Google Chrome)
The operator can be alerted of any of the events by alarms:
- Full Screen Monitoring - an event detected in any channel triggers full screen displaying of the image from the camera; the image can be minimized by double clicking
- Audible Warning
- Notify Surveillance Center - the information about an event is sent to a client application installed on a PC (e.g. iVMS-4200)
- Send E-mail - email notification is sent to the previously entered email addresses
Switches for small businesses.
Smart switches are economic devices for small and medium companies. They have useful security features. Storm control function prevents traffic on a LAN from being disrupted by a broadcast, multicast, or unicast storm on a port. QoS (Quality of Service) in the 2, 3 and 4 layers provides enhanced capabilities to optimize data traffic. In addition, the ability of easy management via a web browser or command line allows quick configuration of the devices. Smart switches are ideal for businesses and workgroups looking for economical, high-speed devices.The table below groups network switches offered by DIPOL. It is easy to choose the most suitable switch for a given application, taking into account the functions mentioned above, number of ports, PoE option (for powering network devices connected to the switch), IGMP snooping function (in the case of multicast traffic).
 |  |  |  |  |  |  | |
| Name | TL-SF1005D | TL-SF1008D | TL-SF1016D | TL-SL1226 | TL-SF1008P | TL-SG1005D | TL-SG1008D |
| Code | N29915 | N29918 | N29926 | N29929 | N29930 | N29935 | N29938 |
| Number of 10/100 Mb/s ports | 5 | 8 | 16 | 24 | 8 | 0 | 0 |
| Number of 10/100/1000 Mb/s ports | 0 | 0 | 0 | 2 | 0 | 5 | 8 |
| Number of PoE ports | 0 | 0 | 0 | 0 | 4 | 0 | 0 |
| RACK-mountable | No | No | No | Yes | No | No | No |
 |  |  |  |  |  |  | |
| Name | TL-SG1024D | TL-SG1016D | TL-SL2210WEB | TL-SL2218WEB | TL-SL2428WEB | TL-SL2452WEB | TL-SL5428E |
| Code | N29939 | N29940 | N29949 | N29950 | N29951 | N29952 | N29955 |
| Number of 10/100 Mb/s ports | 0 | 0 | 8 | 16 | 24 | 48 | 24 |
| Number of 10/100/1000 Mb/s ports | 24 | 16 | 1 | 1 | 2 | 2 | 2 |
| Number of SFP slots | 0 | 0 | 1 | 1 | 2 | 2 | 2 |
| Category | - | - | smart | smart | smart | smart | managed |
| RACK-mountable | No | No | Yes | Yes | Yes | Yes | Yes |
| | | | | | | |
| Name | TL-SG3424 | TL-SG316 | TL-SG3210 | TL-SG3424P | TL-SG2216 | TL-SG2424 | TL-SG108 |
| Code | N29957 | N29958 | N29959 | N29961 | N29947 | N29948 | N29943 |
| Number of 10/100 Mb/s ports | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Number of 10/100/1000 Mb/s ports | 24 | 16 | 8 | 24 (PoE) | 16 | 24 | 8 |
| Number of SFP ports | 4 | 2 | 2 | 4 | 2 | 4 | 0 |
| Category | managed | managed | managed | managed, PoE | smart | smart | (IPTV-IGMP snooping) |
| RACK-mountable | Yes | Yes | Yes | Yes | Yes | Yes | No |
New products offered by DIPOL:
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Worth reading:
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As compared to most competitive solutions, Terra headend allows for more efficient use of bandwidth and channel capacity... more
The configuration of the modules used to convert DVB-S/S2 channels into DVB-T multiplex
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