Wednesday, July 29, 2009

So, what is all this talk about MESH Networks?

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A MESH network is a type of Local Area Network (LAN) that utilizes redundant and distributed nodes connected to one another to route data, video and audio.

Wireless MESH networks were originally developed for use in military applications but, over the past decade, they have undergone significant changes and upgrades to make them available for the civilian market. As the costs to build the radios went down, single radios evolved to support more radios per MESH node with each radio having the ability to provide specific functions and able to support multiple radio cards operating at different frequencies. Many MESH Networks are able to operate across multiple radio bands.

These types of networks are very reliable and provide a redundant system. MESH networks were designed to be self-healing; meaning the network would be able to continue operating when one or more nodes goes down.

So what does this mean? Say, I have seven radios hooked up in a MESH and number 3 and 5 go down, number 2 will just skip number 3 and head on to number 4 and 4 will skip 5 and head to 6 and vice-versa. I never lose my signal and the video/audio/data gets to where it needs to be.

Ok, they sound great – but what are the downsides to this kind of system? The biggest drawback to full mesh networking is the expense involved because of the number of cables and connections that are required. In very large areas there have to be hard-wired nodes every few miles, instead of only wireless nodes, to maintain reliable connectivity.


However…


MACH“ing” the MESH:
Wireless MESH networks are pretty good and they benefit most applications, but not all. Within a planned topology, to provide efficient network access to fixed and portable IP devices which require low to medium bandwidth demands, a MESH radio network is a great way to do this. However, when using multiple individual devices with varying high bandwidth demands, a MESH network topology is not necessarily the best way to transfer this data. This is especially true in the video surveillance industry where high bandwidth requirements for real-time IP video are sometimes necessary.

MESH radio networks (like other IP radio networks) are susceptible to RF interference, bandwidth degradation and network latency. There are sophisticated MESH radios with features like self discovery, self tuning and self healing that do a better job contending with these issues, but they are 3 to 5 times the cost of a traditional IP radio like the MACH-V. The MACH-V radio can be configured as a point to point, point to multi-point or as a wireless distribution system (WDS). In WDS mode, and with careful consideration of bandwidth restraints, a series of MACH-V radios can be deployed to provide some of the same functions as a MESH radio network but at far less cost.

Below is a sample scenario where the MACH-V is used in place of MESH radios:

MESH/MACH DWG


One can’t deny the positives of a mesh radio network particularly the flexibility, scalability and its configuration tools but, in this current environment of budget restraints, the MACH-V is an economical solution that will meet many of the goals of a mesh radio network.


~The WTI Team


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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

www.gotowti.comwww.wirelesstech.com

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Wednesday, July 22, 2009

Blowin’ in the Wind

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One of the environmental parameters of a pan-tilt-zoom camera, which is difficult to test in a conventional test lab or with a home-brewed test setup, is the ability of the camera to withstand strong wind conditions without having its viewing direction influenced. Testing the ability of the camera to stay focused on target in high winds requires a visit to your local wind tunnel.

1 : 070709 : Wind Tunnel

WTI took a trip to the San Diego Air & Space Technology Center to test our Sidewinder camera in their low speed wind tunnel. In the context of the aeronautical community “low speed” means below MACH 1, the speed of sound. The wind tunnel at the San Diego Air & Space Technology Center is capable of generating sustained wind speeds of up to 250MPH!

3 : 070709 : Wind Tunnel

2 : 070709 : Wind Tunnel

The San Diego Air & Space Technology Center is the only privately held low speed wind tunnel in the United States. Most of the testing done at the center is aeronautical in nature, and the center has been involved in the testing of such well known aircraft as the F-106, B-58, F-111, F-16, Global Hawk UAV, Tomahawk Cruise Missiles, and Advanced Cruise Missiles. More recently, the center has become a Mecca for top level cyclists and luge racers who are trying to gain every possible competitive edge, by refining their equipment and body position profiles for the least possible wind drag.

4 : 070709 : Wind Tunnel

The heart of the wind tunnel is the 22,000 horsepower electric motor that drives the turbine blades. The motor is the original motor that was installed in 1947. The turbine blades have been upgraded and replaced over the years to improve the performance of the wind tunnel. The air flow is re-circulated through the oval shaped tunnel to improve the efficiency of the tunnel. The tunnel walls actually form part of the building structure itself!

Once the air has been accelerated by the electric turbine, the turbulence is removed by passing the air through a honeycomb-shaped array of tubes. The air flow is then funneled and channeled into the 8 foot tall by 12 foot wide test chamber area. This is where the testing actually takes place.

5 : 070709 : Wind Tunnel

Testing is monitored through the viewports on the sides of the test chamber, since it is not a good idea to be inside the chamber when the turbine is powered up! If you were to stand inside the chamber, leaning into the wind, at about 80MPH the force of the wind would overcome the friction of your shoes on the floor and you would be swept away down the tunnel. Some adventurous TV weather broadcasters once volunteered to be tethered inside the chamber to see how much wind force they might be able to withstand while doing remote broadcasts during hurricanes. At about 120MPH facing into the air flow, it became difficult to exhale and the pummeling by the wind became very severe, resulting in the testing being stopped.

6 : 070709 : Wind Tunnel

The primary result of our testing showed that it requires a wind speed of over 120MPH to overcome the holding torque of the stepper motor drive and move the camera off position with the Sidewinder camera positioned directly into the wind as shown above. We were very pleased to learn that our camera performed so well in this sort of extreme condition.

7 : 070709 : Wind Tunnel

WTI performed a variety of tests in the tunnel to determine just how much wind force the Sidewinder camera was able to withstand, without the viewing angle being affected. Some of the tests were run on a specially instrumented camera, allowing us to precisely measure the torque applied to the camera components at different wind speeds and with different camera angles. The measurements that we made this day are going to help us improve the performance of the Sidewinder camera even more in the future.

8 : 070709 : Wind Tunnel

All in all, it was a very fun and interesting day at the San Diego Air & Space Technology Center.

~Dale Roche, Director of Engineering



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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

www.gotowti.comwww.wirelesstech.com

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Wednesday, July 15, 2009

Ventura’s Police Department has a new recruit! WTI’s Sidewinder camera.

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In the beginning of July, the City of Ventura’s Police Department installed WTI’s revolutionary Sidewinder P/T/Z camera on the top of the mast of their mobile command center. The Sidewinder has been used as a mast camera for the broadcast industry, fire departments and now our local law enforcement. It is the perfect mast camera because it will see all of the surrounding areas with its super fast pan, tilt and zoom functions.

July 2009: VTA PD

The Ventura Police and Fire Mobile Command Post is used all over the county at community events, emergency situations and crime scenes; incorporating the Sidewinder into law enforcement projects provides exceptional exterior video surveillance at any location. The Ventura Police Department is always on the cutting edge of technology and they have been the example for many departments all across the nation. Having the Sidewinder on top of their command post mast is just another example of their high-tech and innovative philosophy at work.

July 2009: VTA PD

The Sidewinder is a color day, black and white nighttime DSP camera with electronic image stabilization. It has continuous 360° rotation in both pan and tilt axes. Its 35X optical zoom lens gets great close-ups to help law enforcement with suspect identification. It also has a high-tech electrically conductive and hydrophilic “self cleaning” glass face-plate window with a thermostatically controlled heater.

So watch out bad guys because the Sidewinder is watching you!

~Lester Miyasaki, National Sales Manager



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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

http://www.gotowti.com/http://www.wirelesstech.com/

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Wednesday, July 8, 2009

The Digital Video Transition

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Now that the Government has finally mandated and implemented the conversion from analog video to digital video, the security industry is finally going to progress at warp speed in unleashing a storm of new and exciting, and yes user-friendly, products that take full advantage of this technology. There is zero reason to be even thinking Analog anymore! Analog video has served us well but it is time to move on! Personally, I thought that by now the industry would be much further along the digital path that it has.

MPEG H.264/AVC is the latest and greatest compression technology. The purpose of H.264/AVC is to create a new standard which is capable of providing good quality (D1) performance at much lower bit rates that the previous standards. This new standard uses half or less the bit rate of MPEG-2, H.263, or MPEG-4 Part 2. The nice thing about H.264 from the technical standpoint is that it doesn’t increase the complexity of the design very much and it will not be overly expensive to implement from both the hardware and software sides if the isle. An additional and very important aspect of H.264 is the fact that will provide enough flexibility that will allow it to be used in a variety of network applications with the ability to scale both high and low bit rates depending on the application. Both the Blu-ray Disc format and the now-discontinued HD-DVD format include the H.264/AVC high profile as one of 3 mandatory video compression codecs. Sony has also chosen this format for their memory stick video format.

OldCodec
An early version of WTI’s MG400 MPEG Codec from the year 2002 – It was big and it was slow!


Codec
WTI’s current Video Encoder: It’s Small and fast and scalable!


For more information on WTI’s C-MAX Ultra Video IP Encoder and Video Server, check it out on our web site at
http://www.wtipower.com/Products_UltraVideoEncoder.htm.

~Dan Fancher, President/C.E.O.



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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

www.gotowti.comwww.wirelesstech.com

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Wednesday, July 1, 2009

Voice over IP Technology

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Many products that were traditionally based on standard analog and digital technology have advanced rapidly. This advancement is largely due to the implementation of internet protocol (IP) technology in their design. Here in the video industry “video” cameras, transmission, management, recording and archiving have made gigantic leaps in functionality and flexibility due to IP technology. Within the video industry alone, there are many examples of the impact made by IP technology but, today I want to touch on a Telecommunication industry innovation VoIP (Voice over Internet Protocol).

In 1995 the first commercial IP phone software was released by VocalTec. Its success created a foreseeable future where the internet and local area networks (LANs) could be used as an alternative to the traditional public switched telephone network (PSTN). This positive outlook jump-started the VoIP industry and is the reason we have IP phone services like Skype and Vonage today. Statistics show that over 22 Million U.S. households are connected by VoIP and that number is projected to reach 30 Million by 2011 and generate over $11 Billion in revenue for Telecom companies.

VoIP works by converting voice in to a digital signal and then transmitting it over the internet, or LAN, to another VoIP device. The targeted VoIP device will authenticate and receive the signal while converting it back to voice. This communication works in the same manner in which an IP networked PCs communicate to a printer on the same network. Essentially, all network devices communicate to each other through the Internet Protocol Suite (TCP/IP) model or Open Systems Interconnection (OSI) model. The OSI and TCP/IP models provide the communication standards to which all network devices exchange through. Hence, a VoIP phones find each other the same way an IP camera finds a NVR or how this blog reached your computer screen. The diagrams below show two typical VoIP setups:



VoIP DWG 1



VoIP DWG 2




VoIP will continue to improve and prosper because of the following: low cost of its infrastructure, flexibility, extend functionality at a minimum cost, interoperability with traditional PBX, allows for the convergence of voice, data, cell phones, Wi-Fi phones and VoIP can be used over any broadband source: Fiber, Cable, DSL, Wi-Max and Wi-Fi.

VoIP is an innovation that “endows resources with a new capacity to create wealth,”-Peter F. Druker and also “Offers promise of so much to so many in so short a time.”-Bill Gates.

http://www.vocaltec.com/site/content/t1.asp?Sid=5&Pid=2

http://about.skype.com/

http://www.vonage.com/help_vonage.php?refer_id=WEBFT0706010001W1

~ Eric Myers, Director of Wireless Products

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WTI (Wireless Technology, Inc.)

Video Surveillance Products Dedicated to the Broadcast, Global Security and Transportation Markets!

www.gotowti.comwww.wirelesstech.com

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