How IP-based Video Surveillance Works -- Way Beyond Analog

When you're shopping around for an IP-based video surveillance system, you will need to be particularly cautious about what exactly you're looking at and what the individual terms mean. How IP-based video surveillance works is open to interpretation as far as some video surveillance and security salespeople are concerned -- not because they are trying to confuse the issues, but because there is no genuine consensus on what the term "IP-based" or related ones such as "networked" or "web-based" means.

Originally video surveillance was done based on analog technology -- closed
circuit television (CCTV) and recording on video tapes. This was fine for
recording what was going on, but it didn't broadcast actual live information, so
it wasn't practical for monitoring stores, for instance, from a remote location.
It simply provided what happened after the fact. The picture quality wasn't
great and it relied on human reliability as well -- someone had to remember to
change the tapes regularly, etc.

Digital revolutionizes video surveillance

With the Internet revolution and the ever-increasing presence of Local Area
Networks, technology took great strides in video surveillance in the 1990's.
Analog camera tubes were replaced with CCD (Charged Coupled Devices) and digital
cameras became affordable for most people.

This combination meant that video surveillance could do two things: go live
over the Internet or a closed network for surveillance and provide clearer,
crisper images that could be tracked and manipulated easily. For law
enforcement, digital surveillance meant it was much easier to zoom in on images,
track particular scenes and enhance features.

The basics of IP-based surveillance

A digital camera "views" the scene in front of it, broadcasts the video
images as a digitized signal over a LAN line (Local Area Network) where it's
then transmitted to a computer or server. The server in turn manages all of this
information. Depending upon the software used to manage the digital images, it
can record, display or retransmit the images to anywhere in the world.

The software package can easily be upgraded to allow for analyzing data,
selecting specific "flagged" items to watch for and a host of other functions,
making it a truly customizable security tool.

True IP-based digital surveillance uses CCD cameras that use signal
processing that send packetized video streams over the LAN through a Cat 5 cable
rather than a coax cable network, utilizing greater bandwidth and standard
TCP/IP communication.

It also provides more intelligent data mining and information retrieval. If
security is an issue, full digital surveillance also offers the added advantage
of data encryption opportunities to protect against image tampering -- something
not possible with analog recording.

Recently, a few companies such as D-Link and Linksys have also developed fully
digital cameras that actually have completely integrated, built-in web servers
so that no external computers are needed for operating them. The signal is
transmitted directly to the terminal location for storage or play-back.

Halfway there...

The "middle of the road" of video surveillance is upgrading video
surveillance by utilizing a Digital Video Recorder (DVR). A DVR system is not
really fully IP-based, but is step toward the more advanced IP technology. In
actuality, a DVR system uses the same camera and structures for cabling as the
older CCTV analog systems, but the old VCRs have been replaced with DVR for
storage of the data. The data is converted to digital so that it can be stored
on hard disks, but the quality of the images captured remains analog since this
is how it originated.

When shopping for a system, be sure to ask if the system is digital based on
the recording (DVR) or on the camera, since many manufacturers consider a system
digital by virtue of the DVR storage system even if the camera recording the
images is still analog.

Going all the way

Some people will move to the hybrid models of a CCTV/DVR system when they
first move beyond an analog system because it seems like the next practical
evolutionary step in video surveillance. However, shifting to this method
largely ignores how IP-based video surveillance works.

With CCTV/DVR surveillance you have actually simply delayed the inevitable by
adding on a relatively new technology (hard disk, digital storage) to an old
technology (analog video over coaxial transmission lines). Rather than moving
forward into something new, you have prolonged the demise of the old.

Advantages of IP-based video surveillance

The leap into completely IP-based technology is the best bang for your buck
both monetarily and in terms of security by far. Digital surveillance can be
done over a LAN network, of course, but TCP/IP transmittal of surveillance makes
sense for remote monitoring of multiple locations and for remote recording of
data onto back-up servers and hard disks for long-term storage.

With IP-based video surveillance, you can connect your surveillance camera or
cameras to any network or wireless adapter, and you are extremely flexible in
your placement of the camera itself. A typical PC-attached video camera, while
providing digital picture image quality, still has to be within approximately
ten feet of the computer itself.

Set-up of an IP-based video system is easy -- once you've set up an IP
address, you're up and running and it's extremely stable and reliable. Because
this is the technology of the future, it is also upgradeable. You won't be
outgrowing an IP-based video surveillance system any time soon because new
developments are based on improving this market. Therefore, you will be able to
add on and improve this system for years to come while older, CCTV+DVR hybrids
will dead-end and become obsolete.

Comparing analog and IP-based video surveillance

A better way to understand the differences between analog and IP-based video
surveillance may be to compare the two and how they work:

Analog or CCTV+DVR video surveillance

o Easy to use -- operates like a VCR

o Changing cassettes and rewinding regularly means human error frequently interferes with effectiveness

o Image quality is poor

o Storage tapes wear out over time

o Broadcasting images live isn't practical

o Storage is bulky

o Uses analog recording, recording in low-grade picture quality and inability to search and track easily

o Adding DVR systems must be done in 'blocks' of 16 channels

IP-based video surveillance

o IP-based recording means instant transmittal of images anywhere in the world

o Can monitor multiple cameras from one remote location

o No decrease in recording quality over time or with repeated replays

o Digital picture quality far superior to analog

o IP-base recording is highly compressed for easier storage and can be transported over a variety of media

o Digital images can be encrypted for security purposes

o Updates and add-ons are relatively inexpensive through software packages and Internet computer networking

o Adjustable frame rates

o Remote or shared viewing may be done over the Internet or a wireless connection

o Standard IP video compression techniques are used

o IP surveillance cameras may be added individually or in groups according to your needs

If you are contemplating increased or upgrading video surveillance for your
company or home, understanding how IP-based video surveillance works will make
your decision easier. It is the future of video surveillance and, although in
the short term may be a bit more expensive, is obviously an investment in
superior quality and flexibility.

This article on "How IP-based Video Surveillance Works" reprinted with
permission.

Copyright © 2004-2005 Evaluseek Publishing.

Testing a Transformer - How To Accurately Test A Transformer

There is two types of transformers in the market- linear transformer and switch mode power transformer. The transformers design is different. Sometimes it is just referred as ac transformer. Linear transformer mostly used in radio, project kits, VCD and etc while switch mode transformer can be found in Monitor, Tv, Fax and so on.

A transformer consists of two or more coils wound on the same core. For power transformers, the core material is usually iron. For a radio-frequency transformer, the core material is usually ferrite or air. The basic property of a transformer is to change AC voltage. A transformer cannot change direct current voltage. A step down transformer has a lower AC output voltage at its secondary winding than the AC input voltage to its primary winding. Conversely, a step up transformer has a higher secondary than primary voltage. The transformer laminations or coating of shellac, enamel or varnish is to insulate adjacent turns from shorts between winding. I will not go too details about how transformer work and transformer calculation as you can read more details from most electrical and electronic transformers books.

How to test transformers: Transformer failures are relatively rare in most electronic equipment, compared with other components. If too much current goes through a coil or winding, the winding heats up and can either open up completely, or the insulation between turns of wire can break down, causing the coil to be partly or completely shorted.

Just like a coil, you can check continuity of any primary or secondary transformer winding. The actual value of DC resistance you read is rather meaningless, but at least you will know whether a winding is open. Checking linear transformer is quite straight forward. Apply the ac voltage to the primary winding and expect output voltage at the secondary side. No or low output voltage means the transformer winding has open or shorted winding. Look for any evidence of overheating, such as darkened or blackened areas or a burnt smell.

About how to test a power transformer-it is a little bit complicated. You cannot apply ac voltage to the equipment and expect the desire output at the secondary side without connect to load otherwise over voltage will happen (because you have removed all the secondary load) and will blow the power section which consist of power fet, pwm ic and etc. Switch mode power supply are designed to run with load while linear transformer can be test without load.

The best way to test a switch mode power transformer is first remove it from the board. Check only the primary winding as secondary winding failures are exceedingly rare. How do we know which one is the primary winding? Trace from the big filter cap the positive pin to see where the circuit goes. It will go to one of the pin of the transformer. Then look for the power fet middle pin which is the Drain and it will lead to another pin of the transformer. This two pins is the primary winding of the transformer. Checking the resistance of the primary winding only can reveal whether it is open but it cannot check if it has developed a shorted winding. Only by using a ringer test you will know if it shorted or not. A shorted turn in the primary winding can cause the power section to blow.

The cheapest ringer tester that i came across is Dick Smith LOPT METER or flyback tester. Just connect the probes to the primary winding and the result are instantly seen from the Led bar graph. 4-8 bar represent a good winding, 1-2 bar represent partial short and if the led goes off means there is a heavy short in the winding. Besides checking the transformer it can be use to check B+ COIL, horizontal yoke coil and flyback primary winding and ballast (choke).

The expensive ringer tester is from sencore equipment. Sencore LC102 and LC103C besides checking capacitor it also have the capability to check all kind of winding. Whether it is a low voltage transformer, high voltage transformer, current transformer, pulse transformer, electric transformer, custom transformer this equipment will be able to check and test it.

If you do not wish to invest on this tester you may use a light bulb to check it. Remove one of the primary winding pin and connect a 60 watt light bulb. One end to the circuit while the other to the transformer pin. If the bulb light and didn't goes off suspect a shorted winding and if the light goes off, the winding is ok.

Transformer repair is not easy and it require a good skill to do it. Most of the transformer repairer preferred to rewind bigger winding such as fan, car alternator and starter. Switch mode power transformer is a little bit difficult to rewind because of the small size and low price.

How to choose the best Flat screen TV

Choosing the right technology

Plasma and lcd tvs look the same, but they are not. Some features or options don't differ a lot, but these are the major differences:

Size

If you arfe looking for an extra large TV, go for a plasma. Plasma TVs are the current size champions, particularly when comparing TVs that consumers can easily purchase. LCDs are catching up in size with their developing technology, however, and may surpass Plasmas in the near future. This may be due to difficulties in producing glass large enough for larger plasmas.

Burn-ins

With the latest plasma technology, this is less of an issue than ever before. The Pixel Orbitor, for example, is a method of reducing burn-in used by plasma manufacturers. It requires no additional programing from the end user as some older burn-in prevention techniques did.
Note: If you plan to use a plasma for gaming, some games with permanent 'dashboards' may still cause some burn-in. If you will be using the television for display use only, go for an LCD. Plasmas are more likely to get burned-in pixels.

Miscellaneous

- lcd tvs are far less fragile than plasmas. This is also an advantage when the tv set has to be shipped or moved to a different location.

- LCD TVs are also much easier to install than plasma TVs.

- LCD TVs have a better performance at high altitudes.

- LCD TVs are often cheaper than plasma TVs. The difference in pricing is getting smaller, however.

Ofcourse, all this information is available all over the web. For a detailed comparison sheet, I recommend using Wikipedia's comparison sheet.

Flat Screen TV comparison, don't get it wrong

If you have made a choice between plasma and LCD (I'll name it Flat screen TV from now on), you can pick a TV of your choice. Flat screen TV comparison will able you to find out exactly what you want and what'll fit the budget.

Brands

The following brands are being considered as the best manufacturers of Flat screen TVs:

- Hitachi

- Panasonic

- Philips

- Pioneer

- Samsung

If you are looking for a product with outstanding quality, we recommend choosing one of these brands.

Features

Different Flat screen TVs have different features. Most of these features look the same, but there are a couple of unique features as well:

- Ambilight

- HD ready or not?

- Picture in Picture

There are lots of comparison website available, but you will have to know how to use them. Filter the models by brand, price and features and the choice will be a lot easier.

How To Repair Dell E173fpb LCD Monitor Easily

Troubleshooting DELL E173FPB LCD Monitor with power blink symptom is quite easy if you know the right procedure to test it. There are two sections in the monitor that can cause power to blink. It is either primary or secondary section or even sometimes both sections can be faulty. So to isolate as which section is giving problem. I used an automobile 12 volt light bulb (brake light) and connect it between the 12 volt supply line and cold ground with the fuse removed. If the bulb still blink chances is very high the power primary section have problem.

Do not overlook the other voltages line as well such as the 3.3 and 5 volts. If any components shorted that gets the supply from the 5 and 3.3 volts, the power also may blink. If the 12 volts bulb lights up we can assume that the power supply is working fine and something shorted further down the line that makes the power supply to blink. If the bulb lights and you continue to check the power section, it will be going to waste your time. You should now concentrate on the secondary section circuit such as the four transistors C5707 that drive the high voltage transformer in the inverter board.

Just think these transistors like horizontal output transistor (HOT) in the CRT monitor that drive the flyback transformer where it worked so hard and chances for it to breakdown is very high. Checking the four transistors off board found one of them have a shorted reading with an ohmmeter.. This transistor can get faulty by itself or it could be some others components that caused it to develop a short circuit such as a defective high voltage transformer but all of the four high voltage transformers checked to be okay with ringer and ohmmeter test.

Now, here is the secret that I'm going to reveal. If you just replace the defective transistor only, chances is very high the transistor or another C5707 transistor will breakdown again. Usually what a technician does is to test the other transistors with either an analog or digital meter. If you use both meters to test the transistors then you have missed out on the faulty transistor because both meters won't reveal to you the hfe reading of the transistors. Only some digital meters have the hfe checking feature. In other words, you have to use test the hfe reading of a transistor. Although you can replace the other three transistors directly, why not we do some detective work to find the cause of the problem?

Using the Peak electronic atlas component analyzer, I could clearly see the different between a good and a bad transistor. A good C5707 transistor has hfe reading from 320 to about 390 but the bad one reads 467! The other two C5707 transistors have reading about 350. In the above case only two C5707 transistors were replaced and you save the other two. I had burn in test this LCD monitor for many days and it worked perfectly fine.

Conclusion- Whether you repair the DELL E173FPB LCD Monitor or any other model such as the E172FPB or E171FPB, basically the testing method is the same. You could also use this testing procedure on other brand of LCD Monitor too.

LCD TV - A Very Simple Buyers Guide

People tend to get caught up with the numbers game when shopping for electronic gadgets and appliances such as the television. Manufacturers use a lot of techno mumbo jumbo in presenting their products to the consumers. They ramp up the megapixels, the contrast ratio and any other product specification they can come up with because they know that the higher the numbers, the more people get interested. The funny thing, however, is that majority of shoppers probably do not even understand what those numbers mean and what they actually do for the product they are buying. The same techno mumbo jumbo usually gets lost in the translation and shoppers fall into the pit of analysis paralysis. Or worse, people end up spending more for a product that has been made to appear more advanced because it had more pixels on it.

Buying a flat screen television such as an LCD television should be one of the easiest thing to buy. This is especially true today as the lcd tv technology has advanced far enough that further enhancements in the features that count will not be as significant and perceivable as when the technology was still in its infancy.

There are only 4 things you should watch out for in buying a flat screen TV and they should not involve too much of the numbers.

PICTURE QUALITY. When buying an lcd tv, follow your eyes. Here is where most shoppers get too hung up on. They look at the specification sheet more than the LCD screen. But all you have to do to check on how good the specs are is look at the screen! Much of the numbers being thrown around by the manufacturers and dealers definitely would play into this but it should all boil down to how they look on your eyes. Megapixel count, contrast ratio and motion response should not matter if the picture already looks great.

POWER CONSUMPTION. Join the green movement and get the most energy efficient LCD TV that fits your wallet. This can be simply assessed by looking at the wattage requirement of the television. Go get the one with the lowest wattage. Again, many new models today are incorporating the environment-friendly principles into their features so finding units that are energy efficient should no longer be hard.

WARRANTY. This is pretty self explanatory. You should get one with the longest possible warranty coverage. I will advise against paying for an extended warranty but this is entirely up to you.

PRICE. With the speed the LCD TV technology is developing, and with so many players competing in the fray, you are likely to find units being sold at very good prices out there. Bargains are a usual sight in appliance stores and this benefits shoppers. Go take advantage!

The above list is probably the simplest LCD TV buying checklist you will see out there. Do not get too caught up with the technical aspect that manufacturers and dealers are trying to use to get you into buying that brand new flat screen. Buying a TV is simple--- follow your eyes, your wallet and your common sense and enjoy your new TV!

How Do I Pick the Right LCD TV?

The price and the size are the two most important factors among others in choosing the right lcd tv for you. Buying an LCD television can sometimes be complicated but as you shop, the different brands and size ranges will be easy to remember. In choosing a screen size, the space available in your home must be considered before hand.

Firstly, measure the area and location where you would like to place the TV. Determining the figure will help you decide on what lcd tv fits your home. It is also advised to take a look on the seating and furniture set up so that viewers will have an easy time watching. In case that you don't want to rearrange the furniture, you may want to get a screen size that fits your current configuration. But if you want to make some modifications, you better do it before purchasing the TV.

Secondly, calculate the distance from where you want to put the LCD television to the viewing and seating are. A standard of 10 feet away a 35 inch LCD TV will give a better view. For example, 15-20 feet distance from the television is needed. Just always keep in mind that the larger the television the longer viewing distances it needs.

Another factor to consider is the viewing angles. There are some models that produce better viewing angles. Simply put, the angle of viewing suggests an angle wherein the LCD television can be viewed from the side sooner than the value of the picture starts to degrade.

When you are in the store looking for an LCD television, concentrate and scrutinize the picture quality of the unit. It must satisfy your desire of wanting non-pixelated and clear pictures on your screen. The size must be what you are looking for. The LCD screen size can be easily determined if you stop looking and comparing it from other model units in the store. Just remember to focus on the unit you want to purchase.

Anti-glare coating of LCD must be considered when buying a television. This will help solve your problem on the outside light reflection. However, no matter what model you pick, the amount of light can still pass through that will produce glaring. Remember this when arranging the area where you want to put the television.

In choosing an LCD, the issue on HDTV (High Definition Television) may rise. If you enjoy High Definition Television watching, it is therefore a must that you look for a unit that has HDTV features. You should know the unit price is dependent on the brand and the size so you have to give these factors a thought before purchasing.

The two competing companies in LCD TVs are Sharp and Samsung. The brand is not really an issue so long as you get to purchase a television that caters to your needs and that it works well. Cheap LCD televisions are available in the market but availing these gadgets also requires hard thinking. Remember that you have to get quality for your money. In that light, it is best that you patiently look for discount promos or refurbished units on sale.

Best LED TV 2010-2011

LED TVs have rapidly become incredibly popular, and are clearly emerging as the new standard in televisions. Technically an advanced type of lcd tv, LED TVs have conquered the market enough to fall into a category of their own, and are poised to give older lcd tvs a serious run for the money. The technology allows for a greatly improved picture quality compared to plasma, LCD and DLP TVs. As the price gap narrows between LED TVs and the rest, be sure to check out all the features to choose the best LED TV for you.

Everyone is buying LED TVs, and the smart ones are making sure those TVs are wi-fi compatible. After all, everything is going wireless these days, so why not your TV? Out of all the manufacturers of LED TVs, the brands that stand out by offering wireless capability are LG and Samsung. Out of these two, Samsung is the brand that is generally considered the leader of this particular market.

On the other hand, LG's plus points include the fact that their TVs tend to be less expensive while also getting excellent customer reviews. While you're going wireless, be sure to check that your new audio and video devices fit the bill, too - for starts, you can check out Sony's great new wireless Blu-ray player which comes at an attractive price tag.

Thanks to LED technology, added to which is the new line of semiconductors, video images are sharper than ever - you will enjoy deepest blacks, crisp whites and all-round color vibrancy in an overall viewing experience that is nothing short of spectacular. Higher contrast ratios of 500,000:1 and faster refresh rates at 250 Hz and above mean that you get picture quality that is beyond compare. Lifelike images and crisply displayed motion, even for high-speed content, takes TV viewing into the future.

Not only is the picture quality great on the best LED TVs, but they are designed to use significantly less power. On average, these televisions use 40-50% less power than comparable lcd tvs, making them easy on power resources as well as on your wallet - you'll find yourself paying less each month in utility bills. What's more is that no mercury is used in making these TVs. Mercury is toxic to the environment, and is generally used in LCD TVs so it's great that this TVs are made without this harmful substance.

As a general trend, the best LED TVs in today's market have consistently been coming from Samsung, clearly at the forefront of this technology. Not far behind are brands such as Sony and Toshiba. As the competition gets more fierce, prices of these TVs will consistently be lowered, and quality improved as kinks and bugs are fixed in the performance. Generally speaking it is recommended to go not for the top of the line models but the ones right below, for the best price-and-performance balance to get the best value for your money.

In these cases the performance of the TV is almost always comparable to the top-end model, and features offered tend also to be quite similar, but the difference in price is usually quite significant. In the past months alone, prices on these TVs have been dropping significantly so clearly now is the right time to jump in and buy.