The Role Of Electronic Media In Communication

* Ads by Google Human Capital Management Improve outcomes using integrated workforce management solutions. www.apihealthcare.com Electronic media played a very vital role in communication. It played an important role in highlighting problems in society either through Entertainment Dramas or through News, Electronic Media is a source for common people through which they can raise their voice and highlight different issues they want Government to resolve. Electronic Media has influenced people in developing change in attitude towards different situations. Electronic communication has contributed a lot in business environment. They made business meetings through Video, possible and communicating messages between employees like notices etc possible. Electronic Media also made possible communication between employees sitting in different branches and thus developing an organization more into community with people facing similar tasks. Visit this Blurtit Question for more-Can You Write A Short Note On "Role Of Electronic Communication In Modern Office"? Also visit following Blurtit questions: What Is The Role Of Electronic Media In Communication? What is the impact of communication on management trends and how does electronic communication is playing role in business activities? What Is The Role Of Electronic Media In Today's Society? Anonymous Report Was this answer helpful? Yes | No * Ads by Google Information Security Asia's Leading Security Company. MSS, ISO 27001, Security Audit www.xynexis.com * Novartis Fed. Initiative Arturo Morales to Present at CHI's Tri-Con 2012 www.triconference.com/ird Electronic media played a very vital role in communication. Electronic communication has contributed a lot in business environment. They made business meetings through Video, possible and communicating messages between employees like notices etc possible. Electronic Media also made possible communication between employees sitting in different branches and thus developing an organization more into community with people facing similar tasks. Visit this Blurtit Question for more-Can You Write A Short Note On "Role Of Electronic Communication In Modern Office"? It played an important role in highlighting problems in society either through Entertainment Dramas or through News, Electronic Media is a source for common people through which they can raise their voice and highlight different issues they want Government to resolve. Electronic Media has influenced people in developing change in attitude towards different situations. Source: http://www.blurtit.com/q398993.html * Terms of Use * Privacy Policy * Content Disclaime

20 THINGS YOU CAN DO TO CONSERVE ENERGY

Whenever you save energy, you not only save money, you also reduce the demand for such fossil fuels as coal, oil, and natural gas. Less burning of fossil fuels also means lower emissions of carbon dioxide (CO2), the primary contributor to global warming, and other pollutants. You do not have to do without to achieve these savings. There is now an energy efficient alternative for almost every kind of appliance or light fixture. That means that consumers have a real choice and the power to change their energy use on a revolutionary scale. The average American produces about 40,000 pounds of CO2 emissions per year. Together, we use nearly a million dollars worth of energy every minute, night and day, every day of the year. By exercising even a few of the following steps, you can cut your annual emissions by thousands of pounds and your energy bills by a significant amount! Home appliances 1. Turn your refrigerator down. Refrigerators account for about 20% of Household electricity use. Use a thermometer to set your refrigerator temperature as close to 37 degrees and your freezer as close to 3 degrees as possible. Make sure that its energy saver switch is turned on. Also, check the gaskets around your refrigerator/freezer doors to make sure they are clean and sealed tightly. 2. Set your clothes washer to the warm or cold water setting, not hot. Switching from hot to warm for two loads per week can save nearly 500 pounds of CO2 per year if you have an electric water heater, or 150 pounds for a gas heater. 3. Make sure your dishwasher is full when you run it and use the energy saving setting, if available, to allow the dishes to air dry. You can also turn off the drying cycle manually. Not using heat in the drying cycle can save 20 percent of your dishwasher's total electricity use. 4. Turn down your water heater thermostat. Thermostats are often set to 140 degrees F when 120 is usually fine. Each 10 degree reduction saves 600 pounds of CO2 per year for an electric water heater, or 440 pounds for a gas heater. If every household turned its water heater thermostat down 20 degrees, we could prevent more than 45 million tons of annual CO2 emissions - the same amount emitted by the entire nations of Kuwait or Libya. 5. Select the most energy-efficient models when you replace your old appliances. Look for the Energy Star Label - your assurance that the product saves energy and prevents pollution. Buy the product that is sized to your typical needs - not the biggest one available. Front loading washing machines will usually cut hot water use by 60 to 70% compared to typical machines. Replacing a typical 1973 refrigerator with a new energy-efficient model, saves 1.4 tons of CO2 per year. Investing in a solar water heater can save 4.9 tons of CO2 annually. Home Heating and Cooling 6. Be careful not to overheat or overcool rooms. In the winter, set your thermostat at 68 degrees in daytime, and 55 degrees at night. In the summer, keep it at 78. Lowering your thermostat just two degrees during winter saves 6 percent of heating-related CO2 emissions. That's a reduction of 420 pounds of CO2 per year for a typical home. 7. Clean or replace air filters as recommended. Energy is lost when air conditioners and hot-air furnaces have to work harder to draw air through dirty filters. Cleaning a dirty air conditioner filter can save 5 percent of the energy used. That could save 175 pounds of CO2 per year. Small investments that pay off 8. Buy energy-efficient compact fluorescent bulbs for your most-used lights. Although they cost more initially, they save money in the long run by using only 1/4 the energy of an ordinary incandescent bulb and lasting 8-12 times longer. They provide an equivalent amount of bright, attractive light. Only 10% of the energy consumed by a normal light bulb generates light. The rest just makes the bulb hot. If every American household replaced one of its standard light bulbs with an energy efficient compact fluorescent bulb, we would save the same amount of energy as a large nuclear power plant produces in one year. In a typical home, one compact fluorescent bulb can save 260 pounds of CO2 per year. 9. Wrap your water heater in an insulating jacket, which costs just $10 to $20. It can save 1100 lbs. of CO2 per year for an electric water heater, or 220 pounds for a gas heater. 10. Use less hot water by installing low-flow shower heads. They cost just $10 to $20 each, deliver an invigorating shower, and save 300 pounds of CO2 per year for electrically heated water, or 80 pounds for gas-heated water. 11. Weatherize your home or apartment, using caulk and weather stripping to plug air leaks around doors and windows. Caulking costs less than $1 per window, and weather stripping is under $10 per door. These steps can save up to 1100 pounds of CO2 per year for a typical home. Ask your utility company for a home energy audit to find out where your home is poorly insulated or energy inefficient. This service may be provided free or at low cost. Make sure it includes a check of your furnace and air conditioning. Getting around 12. Whenever possible, walk, bike, car pool, or use mass transit. Every gallon of gasoline you save avoids 22 pounds of CO2 emissions. If your car gets 25 miles per gallon, for example, and you reduce your annual driving from 12,000 to 10,000 miles, you'll save 1800 pounds of CO2. 13. When you next buy a car, choose one that gets good mileage. If your new car gets 40 miles per gallon instead of 25, and you drive 10,000 miles per year, you'll reduce your annual CO2 emissions by 3,300 pounds. Reduce, reuse, recycle 14. Reduce the amount of waste you produce by buying minimally packaged goods, choosing reusable products over disposable ones, and recycling. For every pound of waste you eliminate or recycle, you save energy and reduce emissions of CO2 by at least 1 pound. Cutting down your garbage by half of one large trash bag per week saves at least 1100 pounds of CO2 per year. Making products with recycled materials, instead of from scratch with raw materials, uses 30 to 55% less for paper products, 33% less for glass, and a whopping 90% less for aluminum. 15. If your car has an air conditioner, make sure its coolant is recovered and recycled whenever you have it serviced. In the United States, leakage from auto air conditioners is the largest single source of emissions of chlorofluorocarbons (CFCs), which damage the ozone layer as well as add to global warming. The CFCs from one auto air conditioner can add the equivalent of 4800 pounds of CO2 emissions per year. Home Improvements. When you plan major home improvements, consider some of these energy saving investments. They save money in the long run, and their CO2 savings can often be measured in tons per year. 16. Insulate your walls and ceilings. This can save 20 to 30 percent of home heating bills and reduce CO2 emissions by 140 to 2100 pounds per year. If you live in a colder climate, consider superinsulating. That can save 5.5 tons of CO2 per year for gas-heated homes, 8.8 tons per year for oil heat, or 23 tons per year for electric heat. (If you have electric heat, you might also consider switching to more efficient gas or oil.) 17. Modernize your windows. Replacing all your ordinary windows with argon filled, double-glazed windows saves 2.4 tons of CO2 per year for homes with gas heat, 3.9 tons of oil heat, and 9.8 tons for electric heat. 18. Plant shade trees and paint your house a light color if you live in a warm climate, or a dark color if you live in a cold climate. Reductions in energy use resulting from shade trees and appropriate painting can save up to 2.4 tons of CO2 emissions per year. (Each tree also directly absorbs about 25 pounds of CO2 from the air annually.) Business and community 19. Work with your employer to implement these and other energy-efficiency and waste-reduction measures in your office or workplace. Form or join local citizens' groups and work with local government officials to see that these measures are taken in schools and public buildings. 20. Keep track of the environmental voting records of candidates for office. Stay abreast of environmental issues on both local and national levels, and write or call your elected officials to express your concerns about energy efficiency and global warming. Source :http://www.ecomall.com

www.exploratorium.edu

Aerodynamics Every bicyclist has to overcome wind resistance. Most recreational bicycles in which the rider sits up have very poor aerodynamics. While newer bicycles are being designed with better aerodynamics in mind, the human body is simply not well designed to slice through the air. Bicycle racers are aware of the problem of wind resistance and over the years have developed techniques for reducing it. Bicycle designers and inventors have experimented in developing alternative bicycle designs and HPVs (human- powered vehicles) with an emphasis on better aerodynamic performance. Charley "Mile-a-Minute" Murphy was an early cycling racer. His "mile-a-minute" feat was accomplished in 1899. At that time he traveled faster than the fastest automobile. Notice the large windscreen on the train in front of him which greatly reduced wind resistance. BICYCLE INSTITUTE OF AMERICA Wind Resistance Every cyclist who has ever pedaled into a stiff headwind knows about wind resistance. It's exhausting! In order to move forward, the cyclist must push through the mass of air in front of her. This takes energy. Aerodynmaic efficiency--a streamlined shape that cuts through the air more smoothly--enables a cyclist to travel much faster, with less effort. But the faster the cyclist goes, the more wind resistance he experiences, and the more energy he must exert to overcome it. When racing cyclists aim to reach high speeds, they focus not only on greater power, which has its human limitations, but also on greater aerodynamic efficiency. Aerodynamic drag consists of two forces: air pressure drag and direct friction (also known as surface friction or skin friction). A blunt, irregular object disturbs the air flowing around it, forcing the air to separate from the object's surface. Low pressure regions from behind the object result in a pressure drag against the object. With high pressure in the front, and low pressure behind, the cyclist is literally being pulled backwards. Streamlined designs help the air close more smoothly around these bodies and reduce pressure drag. Direct friction occurs when wind comes into contact with the outer surface of the rider and the bicycle. Racing cyclists often wear "skinsuits" in order to reduce direct friction. Direction friction is less of a factor than air pressure drag. On a flat road, aerodynamic drag is by far the greatest barrier to a cyclist's speed, accounting for 70 to 90 percent of the resistance felt when pedaling. The only greater obstacle is climbing up a hill: the effort needed to pedal a bike uphill against the force of gravity far outweighs the effect of wind resistance. Calculate the Aerodynamic Drag and Propulsive Power of a Bicyclist Fill in the information in the boxes. Velocity is your velocity (mi/hr) as read on a speedometer. + (plus) is forward - (minus) is backward. Wind velocity (mi/hr) is - (minus) if it is a tailwind, + (plus) if it is a headwind (relative to the ground). Weight is in pounds. Grade is the angle of the slope. 0 is flat, 90 is a vertical wall. Click on the "Calculate" button. Notice the drag force and power required to keep you moving at a constant velocity. This calculation requires a JavaScript-capable browser. Notes on the calculator: Please be aware that we've made some assumptions in order to simplify this calculation. For instance, this calculator does not take into account the body position (or size) of the rider in regard to wind resistance. In addition, other factors, such as the coefficient of friction are fixed. Also, if you put in "unrealistic" figures you will get unrealistic results. Finally, please be aware that the "Calories per minute" figure is assuming that the human body is 100 percent efficient--this is not the case (20 percent efficiency is closer). For a more accurate figure try multiplying the "Calories per minute" by a factor of five. Reducing resistance Frame builders and designers have been working on creating more aerodynamically efficient designs. Some recent designs have concentrated on shifting from round tubes to oval or tear-shaped tubes. There is a delicate balancing act between maintaining a good strength-to-weight ratio while improving aerodynamic efficiency. Improvements to wheels have made perhaps the biggest impact. A standard spoked wheel has been described as an "egg beater," creating many small eddies as the tire rotates--creating drag. Disc wheels, while generally heavier than their spoked counterparts, produce less wind drag and turbulence when they spin. Aerodynamic Frame This racing frame uses tear-shaped tubes to reduce drag. While improvements to frames and components have improved aerodynamic performance, the cyclist is the largest obstacle to dramatic improvement. The human body is not very streamlined. Body positioning is important; road cyclists use "drop bars" to allow themselves to reduce their frontal area, which helps reduce the amount of resistance they must overcome. Reducing the frontal area helps riders increase their speed and their efficiency over time. In addition to positioning, small details like clothing can also make a big difference in reducing "skin friction." Tight-fitting synthetic clothing is worn by almost every professional rider, both road and mountain. Many recreational riders are also wearing bicycle clothes for the improvement in aerodynamics as well as comfort. Aerodymanics Page: 1 of 2 Select "Forward" below to continue Bottom Navigation bar Source : © Exploratorium

http://encyclopedia2.thefreedictionary.com

broadcasting (redirected from TV transmission) Also found in: Dictionary/thesaurus, Legal, Wikipedia, Hutchinson 0.01 sec. Ads by Google Digital Analog Design News Read the Latest Electronics Design News & Daily Updates from EW- www.ElectronicsWeekly.com/Design Transmission Solenoids Rebuilt valve body-518-4l60e-saturn 01m-700r4-taat-46re-47re-48re-taat 800700tran.com Mercruiser Parts & Tools Tech advice, manuals Sterndrives and Engines sterndrives.com broadcasting, transmission of sound or images to a large number of receivers by radio or television. In the United States the first regularly scheduled radio broadcasts began in 1920 at 8XK (later KDKA) in Pittsburgh. The sale of advertising advertising, in general, any openly sponsored offering of goods, services, or ideas through any medium of public communication. At its inception advertising was merely an announcement; for example, entrepreneurs in ancient Egypt used criers to announce ship and cargo ..... Click the link for more information. was started in 1922, establishing commercial broadcasting as an industry. Radio became increasingly attractive as an advertising medium with the coming of network operation. A coast-to-coast hookup was tentatively effected early in 1924, and expansion of both audience and transmission facilities continued rapidly. By 1927 there were two major networks, and the number of stations had so increased that interference became a serious problem. Legislation (see Federal Communications Commission Federal Communications Commission (FCC), independent executive agency of the U.S. government established in 1934 to regulate interstate and foreign communications in the public interest. ..... Click the link for more information. ) designed to meet this problem was enacted, and the government has since maintained some control over the technical and business activities of the industry. By 2003, 4,804 commercial radio stations were operating in the original AM (amplitude modulation) broadcast band. Commercial broadcasting on the FM (frequency modulation) band began in 1941. The number of FM stations passed the number of AM in 1983; in 1998 there were 6,179 commercial FM stations on the air, and 2,400 noncommercial stations. Experiments in broadcasting television began in the 1920s but were interrupted by World War II. In 1996 there were 1,340 commercial television stations on the air, and 600 noncommercial stations. There were also more than 2,000 low-power television stations. The Corporation for Public Broadcasting was established in 1968 as a not-for-profit, nongovernmental agency to finance the growth of noncommercial radio and television; by 2003 the network served more than 200 television and nearly 800 radio stations. New and competing technologies have had a tremendous impact on broadcasting and the ways in which people use it. With the availability of small, high-quality portable and automotive receivers, it has been estimated that less than half of all radio listening takes place in the home. Cable television cable television, the transmission of televised images to viewers by means of coaxial cables. Cable systems receive the television signal, which is sent out over cables to individual subscribers, by a common antenna (CATV) or satellite dish. ..... Click the link for more information. , which reached more than 67% of all U.S. homes by 2003, gave consumers a wider choice of programs from which to choose. The new cable channels, most of them highly specialized in the programming they offer, coupled with the wide availability of videocassettes and DVDs, have reduced the influence of the broadcast networks. Television signals are also now transmitted from satellites direct to household satellite dishes. See radio radio, transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially to the radio receiver. ..... Click the link for more information. ; television television, transmission and reception of still or moving images by means of electrical signals, especially by means of electromagnetic radiation using the techniques of radio and by fiberoptic and coaxial cables. ..... Click the link for more information. . Bibliography See E. Barnouw, A History of Broadcasting in the United States (3 vol., 1966–70); J. R. Bittner, Broadcasting and Telecommunication: An Introduction (1985); S. J. Douglas, Inventing American Broadcasting, 1899–1922 (1997); J. R. Walker and D. A. Ferguson, The Broadcast Television Industry (1998). The Columbia Electronic Encyclopedia® Copyright © 2007, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/ broadcasting Transmission of sound or images by radio or television. After Guglielmo Marconi's discovery of wireless broadcasting in 1901, radio broadcasting was undertaken by amateurs. The first U.S. commercial radio station, KDKA of Pittsburgh, began operation in 1920. The number of stations increased rapidly, as did the formation of national radio networks. To avoid radio monopolies, Congress passed the Radio Act of 1927, which created the Federal Communications Commission to oversee broadcast operations. In the 1930s and '40s, the “golden age of radio,” innovations in broadcast techniques and programming made radio the most popular entertainment medium. Television broadcasting began in Germany and Britain in the 1930s. After World War II, the U.S. took the lead, and television stations soon overshadowed radio networks. Color television broadcasts began in 1954 and became widespread in the 1960s. By the 1980s, satellite transmission of live television further expanded the field of broadcasting. See also ABC, BBC, CBS, CNN, NBC, PBS. For more information on broadcasting, visit Britannica.com. Britannica Concise Encyclopedia. Copyright © 1994-2008 Encyclopædia Britannica, Inc. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. Copyright © 2011 Farlex, Inc.

http://www.crc.gc.ca

Television Systems and Transmission The objective of the Television Systems and Transmission group is to provide the necessary technological knowledge in advanced television systems and transmission technologies to Industry Canada and to the broadcast and telecommunications industry. Fields of expertise include digital television and enhancements to NTSC television. The group supports Industry Canada in meeting its mandate on spectrum management and in developing regulatory frameworks for broadcasting. Guidance is provided to broadcast and telecommunications industries in implementing new broadcast services and developing new equipment. The Television Systems and Transmission group is responsible for monitoring and identifying trends in television transmission technologies and contributing to the planning of future research. The Television Systems and Transmission program is responsible for planning and carrying out a research program in television broadcast signal transmission by: * conducting research in coding, modulation, channel equalization and error correction techniques for the transmission of analog (NTSC) and digital (ATV) television signals over terrestrial off-air, satellite and cable-TV channels; * characterizing transmission channels, in particular terrestrial off-air channels; * developing hardware and software channel simulators; * carrying laboratory and field tests; * developing new concepts for broadcasting services; * studying TV broadcast coverage and spectrum planning tools for digital television systems, such as CRC-COVLAB; * contributing to the development of transmission standards; and * representing Canadian interests in international fora as appropriate. It is also the group's responsibility to design and evaluate the different technologies necessary for the implementation of improved television services and to make sure that Canada selects the best available transmission systems by disseminating information and transferring technology to the industry. For a number of years, the group contributed to the prototype development and evaluation of digital television systems. After years of development, a digital advanced television system standard was proposed by the Advanced Television Systems Committee (ATSC). This standard was adopted in 1996 by the FCC for use in the USA and in 1997 by Industry Canada for use in Canada for over-the-air television broadcasting. For the orderly implementation of digital television broadcasting, critical additional knowledge and information are required with respect to coverage, potential interference with other wireless services and co-existence with the present NTSC analog television during the transition period. Furthermore the ability to use part of the channel capacity for non-programming services such as a variety of data services is an important consideration in the digital television implementation plans of the broadcasters. The user requirements for such services have to be better defined and their technical implications on transmission and distribution techniques have to be assessed. With demand for more video services, new delivery systems are emerging such as Multipoint Distribution System (MDS) and Local Multipoint Communication Systems (LMCS). Interoperability of these various systems and the need to integrate broadcast systems into other information systems and services under the umbrella of the "Information Highway" is another important aspect which has implications on transmission technologies for television service delivery. Further Information: Gilles Gagnon Manager Television Systems and Transmission Tel: (613) 998-5002 Fax: (613) 990-6488 E-mail:gilles.gagnon@crc.gc.ca » * Printer-friendly version * Send to friend * PDF version .sumber: @crc.gc.ca

http://www.collegeofpsychicstudies.co.uk/

Welcome To The College Of Psychic Studies CPSFounded in 1884, the College is a beacon of light and learning for those seeking to explore a consciousness beyond matter. As one of the oldest establishments of our kind, we endeavour to kep in touch with any new developments and educational methods, to continue the College's influential and distinguished history. Our teaching staff, sensitives, healers & counsellors have extensive training in their respective fields and are dedicated to helping with personal, psychic and spiritual development. more about the college Opening Hours The College Monday - Friday 11am - 7pm (phone lines close at 6.30pm) Library Monday - Friday 12.30pm - 6pm Contact Details Telephone: +44 (0)20 7589 3292 Fax: +44 (0)20 7589 2824 Gift Vouchers © 2009 The College of Psychic Studies | Valid XHTML | CSS Home | Membership | Recruitment | Sitemap

TV Buying Guide

What's Your Type?

The television is one of the most significant inventions of the 20th century. For the whole picture, read How Television Works. In the past few years, there have been tremendous leaps in TV technology. Twenty years ago, TV shoppers had very few choices. These days, several TV technologies are competing with one another. This makes TV shopping all the more difficult. Each TV type has strengths and limitations based on the technology being used. Deciding what type of TV is right for you starts with understanding the factors that affect a TV's performance.
Viewing range is an important factor, especially when shopping for a big-screen TV. The viewing angle represents the total area in front of the screen that the image can be seen without distortion. When it comes to viewing range, some TVs are better than others. This is based on the technology used to deliver the picture. For instance, because a plasma TV uses tiny lighted cells to produce the picture, if you are viewing these cells at an angle you will lose picture clarity. A traditional tube TV (CRT) uses a cathode ray to paint the screen with the picture. This method allows for a wide viewing angle.
Black level is your TV's ability to produce the color black. TVs create image color by mixing the colors red, green, and blue. Black is the absence of color and serves to provide detail to an image. Achieving a true dark black is something newer TV technologies such as LCD (liquid crystal display) and plasma are struggling to create. To this day, nothing beats an old-fashioned tube TV (CRT) for black level.
Resolution is the number of pixels per square inch. Pixels are tiny, colored dots that combine to form the picture you see on the TV screen. The more pixels there are on the screen, the higher the resolution. The higher the resolution is, the better the picture quality. Resolution measurements are shown in this type of format: 1280x720. These numbers correspond to the number of horizontal and vertical pixels in the image. To give you an idea of the available range, a CRT TV is capable of up to 480 lines of resolution, while an HDTV can produce 1920x1080. You may see resolution abbreviated to only the second (vertical) number, plus a letter "p" (progressive scan) or "i" (interlaced) -- so, 720p or 1080i.

Burn-in is the term for the damage done to a screen by static images that are displayed for a long time. Both tube TVs and plasma TVs are prone to this kind of damage. When a static image like a stock market crawler, station logo or video game score display is left on the screen for a long time, the image gets burned into the screen by the picture-producing mechanism. Burn-ins will appear as "ghost" images on a screen. The chance of burn in can be reduced on any type of TV by setting the contrast levels at their middle settings and making sure static images are not displayed on a TV for hours at a time. A new technology called auto pixel shift also helps plasma screens resist burn-in.

Glare is created when a TV screen picks up ambient light from the room and reflects it back at the viewer. This is a particular problem with tube TVs that have curved glass screens. To counter this, manufacturers provide flat-screen versions that drastically reduce glare. They are more expensive, but may be well worth the extra money if glare is a problem in your home.
Durability is a desirable trait in anything you buy. Once again, the technologies used are the greatest determining factor in the life span of your new TV. LCDs and CRT TVs are known for their long lives. On the other hand, plasma TVs and projection TVs have much shorter life spans despite their much larger price tag.
Price is an obvious factor when shopping for anything. In the world of TV shopping, price is stacked based on the size and type of television. Plasma and LCDs are more expensive than CRT TVs because the technology is newer and more expensive to produce. The most important thing to remember when TV shopping is that the highest price does not necessarily mean you are going to get the best picture.
Screen size is an interesting limitation that affects all types of TV. The limits are set based on the practicality of implementing a particular type of technology for the screen size in question. For example, a CRT tube TV gets taller and wider as the screen size increases. It also gets deeper and heavier in order to accommodate the larger tube needed to produce the picture at that size. CRTs top out at about 40 inches because any larger would make them impractical. LCDs, which are based on transistors and capacitors, suffer from a similar limitation but for a different reason -- increasing size beyond about 37 inches produces a display that is too likely to contain a bad transistor. Plasma TVs and projectors, on the other hand, really have no limit to screen size other than the price.                                                                                                                                                 

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Use of Electronic Devices

Photographic devices

There is no general University policy about the use of cameras and the transmission of images on campus; various buildings and facilities do have local policies, however, and you should thus always check before taking photographs in University buildings. In any event it is appropriate to ask someone’s permission before taking a picture of them, and before circulating their image or transmitting it electronically.

Where policy does exist, it applies to cameras, and to any other device with photographic capabilities, like a cell phone, a personal digital assistant, etc.

Recreation Buildings: You may not use any photographic equipment in ANY recreation facilities on campus, including but not limited to washrooms and change rooms, without prior permission. To obtain permission, please call 416-946-5125

NOTE: Surveillance cameras: a number of locations on campus are observed by surveillance cameras, which are monitored by the University police for the purpose of crime detection.
Transmission of images and recordings:

If you transmit someone’s image or a recording of them in a way that creates discomfort or embarrassment for them, you may be in violation of harassment policy.

In any situation in which it is not acceptable to take a picture, it is also not acceptable to publish that picture. Transmission of pictures on the internet constitutes publication.

Copyright: Remember, all images transmitted are subject to copyright laws, just like any other digital document.
Electronic Devices
In Class or in Exams:

Cell phones, pagers and other communication devices are prohibited in exams. So are all forms of recording device. If it is absolutely imperative that you be reachable during an exam, get prior permission from the invigilator. Otherwise: turn your phone off.

During a class cell phones and other communication devices should either be turned off or in silent mode. Do not answer your phone in class.

If you want to record a class, ask the instructor’s permission beforehand.
In private rooms:

The used of photographically capable cell phones is not permitted in change rooms or other recreational facilities.

Taking photos or making audio recordings without permission in ANY context in which the person photographed has a reasonable expectation of privacy is prohibited. This includes people’s residence rooms.

Be considerate about when you use your electronic device.

Is it disturbing or distracting others?
Do you really need to use it at this time?
Have you turned your ringer or alarm off?


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Dispenser Pengharum Ruangan

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Dispenser Pengharum Ruangan
Apakah ruangan AC Anda segar dan dingin? Jawabnya pasti iya, tetapi apakah juga wangi?
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Atau Anda memakai pengharum tekan dengan tangan, yang semprotannya seperti pembasmi nyamuk...
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Manitoba Hydro power

Manitoba Hydro power sales trigger development of new hydro
08 June 2011

Premier of Manitoba Greg Selinger has announced that recent agreements signed by Manitoba Hydro for the sale of electricity to utilities in the US will require the construction of new hydroelectric generating capacity in the Canadian province.

In a statement, the Premier said that the agreements for the sale of 250MW of electricity to Minnesota Power and a 100MW sale to Wisconsin Public Service will trigger the development of the 695MW Keeyask Generating Station on the lower Nelson River, 175km northeast of Thompson in the Split Lake Resource Management Area.

Keeyask is to be developed by a partnership consisting of Manitoba Hydro and the Keeyask Cree Nations-Tataskweyak Cree Nation, War Lake First Nation, Fox Lake Cree Nation, and York Factory First Nation. The $5.6B project will provide some 4,500 person-years of construction employment, said Selinger.

“I am very pleased that Manitoba Hydro is moving forward with these power sales which will significantly increase our exports and lead to further development of Manitoba’s renewable hydro power resources,” stated Selinger. “These sales will add to Manitoba’s reputation as a sustainable energy leader and help reduce global greenhouse-gas emissions by reducing the need for thermal generation in the United States. At the same time, the development of Keeyask will deliver jobs, training and business opportunities to the Keeyask Cree Nations, the north and all of Manitoba.”

“Today’s announcement demonstrates there is strong interest in Manitoba hydro power in US markets, resulting in the need to advance construction of new generation and a new interconnection with the US that will broaden and diversify our customer base, increase our revenues and contribute to reliable, cost-effective future electricity supply for Manitobans,” addedd Bob Brennan, president and CEO, Manitoba Hydro.

The 250MW power sale to Minnesota Power over a 15-year period from 2020 to 2035 requires an additional interconnection between Manitoba and the US which will provide increased export capability and reliability benefits for Manitoba, explained Selinger.

The 100MW power sale agreement to Wisconsin Public Service covers the 2021-2027 period. Negotiations are continuing to expand the Wisconsin sale to 500MW which would require construction of the Conawapa Generating Station, the premier said, adding with these sales, Manitoba Hydro and its partners are reviewing scheduling and other requirements for moving forward with Keeyask.

Manitoba Hydro’s construction program also includes the Bipole III transmission line, being developed for a 2017 in-service date to provide reliability for Manitoba customers. Bipole III will also be utilized to transmit power from Keeyask and the 1485MW Conawapa Generating Station, supporting expanded electricity export sales outside of Manitoba’s borders. The Conawapa site is located in the Fox Lake Cree Nation Resource Management Area.

Sale agreements with Minnesota Power and Wisconsin Public Service will require regulatory approval in Canada and the US.

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Teleskop Radio menangkap Citra Terbaik Jet Lubang Hitam
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Selasa, 24 Mei 2011 - Sebuah tim internasional, termasuk para peneliti yang didanai NASA, menggunakan teleskop radio yang berada di sepanjang belahan Bumi selatan menghasilkan citra jet-jet partikel paling detail yang meletus dari sebuah lubang hitam supermasif di sebuah galaksi dekat.



“Jet-jet ini muncul saat materi yang jatuh mendekati lubang hitam, namun kami belum tahu detail bagaimana ia terbentuk dan mempertahankan ujudnya,” kata Cornelia Mueller, penulis utama studi dan seorang mahasiswa doktoral di Universitas Erlangen-Nuremberg di Jerman.

Citra baru ini menunjukkan sebuah daerah kurang dari 4.2 tahun cahaya saja lebarnya – kurang dari jarak matahari kita dengan bintang terdekat. Tampilan pemancar radio seukuran 15 hari cahaya dapat dilihat, membuat ini merupakan gambaran jet galaksi resolusi tertinggi. Studi ini juga akan muncul dalam edisi Juni jurnal Astronomy and Astrophysics dan tersedia secara online.

Mueller dan timnya mentargetkan Centaurus A (Cen A), sebuah galaksi dekat dengan sebuah lubang hitam supermasif seberat 55 juta kali massa matahari. Juga dikenal sebagai NGC 5128, Cen A berada sekitar 12 juta tahun cahaya di rasi Centaurus dan merupakan salah satu sumber radio langit pertama yang diketahui merupakan galaksi.

Dilihat dalam gelombang radio, Cen A merupakan salah satu benda terbesar dan terterang di langit, hampir 20 kali ukuran tampak bulan purnama. Hal ini karena galaksi tampaknya berada di tengah sepasang cuping pemancar radio raksasa, masing-masing panjangnya hampir satu juta tahun cahaya.

Cuping-cuping ini berisi materi yang mengalir dari jet partikel yang ada di dekat lubang hitam di pusat galaksi. Para astronom memperkirakan kalau materi yang berada di dekat basis jet ini berlari keluar dengan kecepatan sepertiga laju cahaya.

Dengan menggunakan array antar benua terdiri dari sembilan teleskop radio, para peneliti yang tergabung dalam proyekTANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry – Pelacakan Inti Galaksi Aktif dengan Interferometri Miliarcdetik Selatan) mampu dengan efektif memperbesar citra relung terdalam galaksi ini.

“Teknik komputer canggih memungkinkan kali menggabungkan data dari teleskop individual untuk menghasilkan citra-citra dengan ketajaman satu teleskop raksasa yang ukurannya sebesar planet Bumi itu sendiri,” kata Roopesh Ojha dari Pusat Penerbangan Ruang Angkasa Goddard milik NASA di Greenbelt.

Keluaran energi besar galaksi seperti Cen A datang dari gas yang jatuh ke lubang hitam seberat jutaan kali massa matahari. Lewat proses yang belum dimengerti sepenuhnya, sebagian materi yang jatuh ini terlontar dalam jet-jet berlawan arah dengan kecepatan mendekati laju cahaya. Citra detil struktur jet ini akan membantu para astronom menentukan bagaimana mereka terbentuk.

Jet-jet ini berinteraksi kuat dengan gas sekitarnya, sehingga mungkin mengubah laju pembentukan bintang di galaksi. Jet berperan penting namun kurang dipahami perannya dalam pembentukan dan evolusi galaksi.

Teleskop antariksa sinar Gamma Fermi milik NASA telah mendeteksi radiasi yang jauh lebih tinggi dari bagian tengah Cen A. “Radiasi ini miliaran kali lebih energetik daripada gelombang radio yang kami deteksi, dan dari mana datangnya masih berupa misteri,” kata Matthias Kadler dari Universitas Wuerzburg di Jerman dan juga kolaborator Ojha. “Dengan TANAMI, kami berharap dapat menjelajahi kedalaman galaksi untuk mengetahuinya.”

Ojha didanai lewat proyek penyelidikan Fermi pada studi multipanjang gelombang Inti Galaksi Aktif.

Para astronom berterima kasih pada kemajuan berkelanjutan dalam Australian Long Baseline Array (LBA) atas peningkatan resolusi dan mutu gambar besar-besaran TANAMI. Proyek ini menggabungkan LBA dengan teleskop-teleskop di Afrika Selatan, Chili dan Antartika untuk menjelajahi jet-jet galaktik terterang di langit selatan.

Teleskop luar angkasa sinar gamma Fermi milik nasa adalah sebuah hasil kerjasama astrofisika dengan fisika partikel yang dikembangkan bersama oleh Departemen Energi AS, berbagai lembaga dan mitra akademis dari Perancis, Jerman, Italia, Jepang, Swedia dan AS. Australia Long Baseline Array adalah bagian dari Fasilitas Nasional Teleskop Australia, yang didanai Pemerintah Australia dalam operasinya sebagai Fasilitas Nasional yang diatur oleh Organisasi Riset Ilmiah dan Industri Persemakmuran.

Untuk multimedia terkait, kunjungi : http://svs.gsfc.nasa.gov/goto?10770

Sumber berita:

NASA/Goddard Space Flight Center.








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Berita dan Fakta Ilmiah Harian (Selasa, 24 Mei 2011). Teleskop Radio menangkap Citra Terbaik Jet Lubang Hitam. FaktaIlmiah. Diperoleh pada Monday, June 13th, 2011, dari http://www.faktailmiah.com/2011/05/24/teleskop-radio-menangkap-citra-terbaik-jet-lubang-hitam.html

Berita dan Fakta Ilmiah Harian. "Teleskop Radio menangkap Citra Terbaik Jet Lubang Hitam" FaktaIlmiah Tuesday, May 24th, 2011. Monday, June 13th, 2011

1. Rekonstruksi Iklim 3 Juta Tahun Lalu membantu Ilmuan Memahami Perubahan Iklim
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3. Lima Perguruan Tinggi Indonesia mengikuti Shell Eco-Marathon 2011
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5. Dampak Ekologis Besar di Garis Pantai Artik akibat Perubahan Iklim Global

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ELEKTRO Online

ELEKTRO INDONESIA Edisi ke Tiga Belas, Juni 1998 TELEKOMUNIKASI
Broadband CDMA : Teknologi Wireless Masa Depan
Banyak industri telekomunikasi sekarang percaya bahwa Code Division Multiple Access (CDMA) spread spektrum akan mengalihkan perhatian pada awal abad 21. Dia akan mengganti teknologi analog contoh AMPS dan kompetitornya seperti GSM.
Pada saat bersamaan B-CDMA yang merupakan model komunikasi baru yang efisien akan berkembang ke arah PCS dan menjadi pilihan umum untuk WLL di dunia.
Broadband CDMA sepenuhnya layak untuk diaplikasikan di WLL, PCS dan wireless berbasis satelit yang akan datang.
Pada versi yang akan datang dari CDMA akan menyediakan servis-servis dengan bandwidth data yang tinggi (termasuk ISDN, video dan multimedia) yang tidak dapat disediakan oleh teknologi narrowband.
Apakah Broadband CDMA?
Standar teknologi CDMA, dilihat dari spread signalnya relative lebih besar dari teknologi selular lainnya, pengurangan problem propagasi (multipath dan fading). Dikenal dua standar untuk aplikasi dengan metode akses CDMA. Standar yang dimaksud adalah IS-95 dan poprietary.

Broadband CDMA mengambil konsep ini lebih lanjut oleh pengurangan multipath-fading, penawaran kapasitas dalam tiap cell dan kualitas suara yang lebih baik. Bandwidth yang luas juga membuat mungkin features ke depan termasuk ISDN dan bandwidth on demand. Broadband CDMA dengan wireless mempunyai potensi untuk menyediakan "transparan" local loop dengan fungsi penuh seperti wireline.

Broadband CDMA sebagai WLL didesain untuk menyediakan layanan fixed dan mobiile yang dikoneksikan dengan PSTN dari layanan POTS (Plain Old Telephone Service) ke features-features selanjutnya seperti ISDN dan bandwidth on demand. Service-service akan termasuk voice, high speed fax, data dan multimedia, termasuk juga video. Teknologi ini memungkinkan aplikasi ISDN ke desktop fixed wiireless dan mobile wireless. Adapun konfigurasi dari sistem B-CDMA adalah :


Gambar 1
Gambar 1. Konfigurasi B-CDMA

Keterangan gambar :
OS (Operating System) : operasi, administrasi dan fungsi maintenance
RDU (Radio Distribution Unit) : interface ke exchange dengan standar V5.1
RCS (Radio Carrier Station) : interface ke RDU via copper, fiber atau Microwave
RNT (Radio Network Termination) : menyediakan koneksi ke analog atau ISDN Telepon, fax dan data modems
Teknologi Broadband CDMA (B-CDMA)
Teknologi B-CDMA dikembangkan dari teknik CDMA. B-CDMA merupakan teknologi alternatif Wireless Acces pada era Digital Broadband dengan penjelasan sebagai berikut:

* Merupakan teknologi digital spread spektrum lanjutan untuk kepentingan komersial, yang memberikan berbagai kelebihan dibanding copper, cable, microwave dan bahkan sistem komunikasi radio lainnya, seperti :

* kualitas suara yang tinggi (32 kb/s)
* karakteristik fade sangat baik
* performansi indoor sangat baik
* dinamik data rate (on demand) : 32 kb/s ~ 144 kb/s

* Pemilihan frekuensi secara fleksibel (300 ~ 2500 MHz)

CDMA pada dasarnya dikembangkan oleh militer di Amerika dan kemudian dikomersialkan oleh perusahaan di Amerika oleh Qualcomm dan dikembangkan dengan standar IS-95. Tipikal frekuensi operasi untuk IS-95 adalah 800 MHz. Versi Broadband yang baru B-CDMA, akan diterapkan untuk tiga band frekuensi :

* DCS 1800 (1,71 sampai 1,785 Ghz, dan dari 1,805 sampai 1,880 GHz)
* US-PCS (1,85 sampai 1,9 GHz dan 1,93 sampai 1,99 GHz)
* CEPT (2 sampai 2,7 GHz)

Perbedaan penting yang lain dengan narrowband CDMA didesain untuk bandwidth 1,25 MHz untuk setiap direction. Untuk B-CDMA pada umumnya menggunakan bandwidth 7 MHz, 10,5 MHz, 14 MHz dan 15 MHz.

Dengan bandwidth yang lebih lebar akan menyediakan level of fade resistance yang lebih besar, yang akan menghasilkkan performansi yang lebih besar untuk output power yang sama, atau mengurangi syarat power untuk menyediakan range coverage yang sama. Selanjutnya, pertambahan bandwidth sangat identik dengan penambahan kapasitas untuk mendukung layanan-layanan dengan bandwidth yang lebih tinggi dan menambah fleksibilitas untuk service gabungan. Dalam arti bahwa satu sistem broadband dapat melayani berbagai macam service secara simultan.

Gambaran dari sistem tersebut adalah sebagai berikut :
Gambar 2 . Sevice Simultan B-CDMA
Aplikasi Broadband CDMA
Broadband CDMA sedang dikembangkan untuk empat aplikasi utama ; rural wireless local loop, urban wireless local loop, personal communications system (PCS), Global Mobile Personal Communcations by Satellite (GMPCS) dan IMT-2000, semua akan digambarkan seperti di bawah ini.
Pasar WLL

Beberapa pengamat percaya bahwa market internasional untuk WLL , secara khusus dari Asia, selama beberapa waktu akan lebih besar daripada untuk cellular atau PCS. Beberapa negara Asia, seperti India mempunyai kurang dari 1 (satu) telepon per 100 (seratus) penduduk dan rata-rata di dunia mencapai 11 atau 12 telepon per 100 penduduk. Perkiraaan untuk waktu dekat bahwa di dunia akan membutuhkan sekitar 1 miliiar telepon dimana setengahnya akan disuplai dari mobile telepon dengan tipe solusi WLL.

Rural WLL

Teknologi broadband CDMA secara khusus pantas untuk area yang sangat sulit atau untuk daerah yang mahal jika diterapkan jaringan kabel. Aplikasi WLL adalah sangat penting untuk negara-negara Asia karena mempunyai penetrasi yang rendah sehingga dapat sebagai pemasangan subscriber yang extra. Sekarang teknologi WLL, khususnya B-CDMA lebih murah diinstal daripada kabel tembaga. Wireless sedang menjadi pilihan teknologi yang ditetapkan pada service fixed telepon yang dikembangkan di dalam area regional Asia dan tempat lainnyya.

Menurut InterDigital, WLL dapat diinstal pada harga di bawah US$ 1.000 per line, dan akan semakiin menurun pada masa yang akan datang.

Urban WLL

Pada daerah urban dan suburban, WLL Broadband CDMA akan menghapuskan atau mengurangi dari pemasangan kabel yang baru.

Broadband CDMA menyediakan generasi yang akan datang untuk teknologi wireless telekomunikasi, dari basik voice melalui 2 Mbps data untuk service mobile dan fix pada residensial, dan lingkungan urban. Sistem juga mampu menyediakan layanan sekualitas wireline seperti voice, fax, ISDN (2B + D) dan service leased line. Broadband CDMA juga mensupport service untuk telepon coin dan telepon smart card.
Sebagai gambaran dari arsitektur dari B-CDMA pada aplikasi WLL adalah sebagai berikut :


Gambar 3. B-CDMA pada WLL

Keterangan :
o FSU :

FSU (Fixed Subscriber Unit) diletakkan di sisi pelenggan, menyediakan line interface untuk menghubungkan telepon analog dan ISDN. Di samping itu juga mendukung untuk aplikasi POTS dan service yang akan datang, leased line, ISDN dan software download baik outdoor maupun indoor.

o RCS :

RCS (Radio carrier Station) merupakan terminasi air interface pada access radio dan merupakan interface dengan RDU (Radio Distribution Unit) melalui link terestrial.

o RDU

RDU (Radio Distribution Unit) menghubungkan ke lokal exchange melalui interface V5.1. Satu RDU dapat dipakai sampai 4 RCS.
PCS

PCS akan menyediakan penambahan level mobility dengan service wideband. Teknologi Broadband CDMA mendukung option dengan range yang lebar dari harga yang paling murah per line dan kapasitas yang paling tinggi untuk service yang akan datang.

Broadband CDMA akan menyediakan portabel handset, mirip dengan selular tetapi availabel untuk data rate yang lebih tinggi.

Handset dengan mobilittas yang terbatas biasanya direncanakan sebagai extension untuk sistem WLL broadband CDMA.

GMPCS

Global Mobile Personal Communications by Satelite akan menghubungkan pelanggan-pelanggan anytime, anywhere di bumi lewat hubungan secara langsung lewat Low Earth Orbit (LEO) atau Intermediate Circular Orbit (ICO), tergantung dari sistem yang digunakan. Terminal dual mode dari sistem GSM dan CDMA akan dapat digunakan pada tahun 2000, dimana service-service komersial akan dimulai.

IMT 2000

IMT 2000 dikenal juga dengan istilah FPLMTS (Future Public Land Mobile Telecommunication System). Untuk aplikasi generasi ke 3 ini masih diajukan proposal kepada badan standarisasi : TIA, ETSI dan ARIB (badan standarisasi di Amerika, Eropa dan Jepang) sebagai syarat pada implentasi IMT 2000. Adapun para vendor dan jenis teknologinya ditampilkan pada tabel berikut :


Regional Standards Body

Technology

Group
TIA (TR 45.5)
IS-95 based wideband CDMA
IS-95 based wideband CDMA
IS-95 based wideband CDMA
IS-95 based wideband CDMA
IS-95 based wideband CDMA
Lucent, Motorola, Nortel, QUALCOMM
NHS
Nokia
Samsung
Hitachi
ARIB
W-CDMA
NTT DoCoMo, Fujitsu, Panasonic, NEC
ETSI (SMG2)
W-CDMA
W-TDMA/CDMA

Nokia, Ericsson, NEC, Panasonic, Fujitsu
Siemens
Keuntungan CDMA
Sebelum dibahas keuntungan dari penggunaan broadband CDMA maka akan dibahas terlebih dahulu kelebihan metode akses CDMA dengan metode akses lainnya (TDMA dan FDMA). Keunggulan CDMA jika diaplikasikan pada sistem selular adalah :

1. Co-exixt dengan selular CDMA
Dua sistem seluler FDMA dan CDMA dapat beroperasi secara bersama-sama. Perancang selular CDMA dapat memberikan solusi dengan memperkenalkan unit bergerak dual mode FDMA/CDMA pada pelanggan.

2. Tidak membutuhkan equalizer
Bila lajju trannsmisi lebih besar daripada 10 kbps dalam FDMA dan TDMA, sebuah equaliser dibutuhkan untuk mengurangi intersimbol iinterference yang dibutuhkan leh timme delay spread. Dalam CDMA hanya dibutuhkan korelator sebagai penggganti equalizer pada penerima untuk despreading sinyal spread spectrum.

3. Satu radio per site
Hanya satu radio yang dibutuhkan pada tiap sel atau pada tiap sektor.

4. Tidak membutuhkan guard time dan guard band
Guard time dibutuhkan dalam CDMA antara time slot sedangka guard band dibutuhkan pada FDMA untuk menjaga interferensi antar kanal.

5. Tidak membutuhkan alokasi dan pengelolaan frekuensi
Pada TDMA dan FDMA, pengelolaan frekuensi merupakan tugas kritis untuk diselesaikan. Karena hanya terdapat satu kanal radio bersama pada CDMA, tidak ada pengelolaan frekuensi yang dibutuhkkan.

6. Soft capasity
Kapasiats sistem CDMA ditentukan oleh interferensi diri. Dalam usaha untuk mempunyai banyak user berkomunikasi secara suimultan, interferensi cochannel memberikan batasan jumlah user yang aktif secara simultan.

7. Soft handoff
Soft handoff dapat dilakukan dalam CDMA karena setiap sel menggunakan frekuensi yang sama.

8. Proteksi dari penyadapan dan jamming.
Anti sadap dan jamming secara inheren terdapat dalam sistem komunikasi spread spektrum.


Keuntungan utama dari solusi Broadband CDMA adalah flexibilitas. Sistem CDMA menyediakan untuk aplikasi komunikasi pada skala besar dan kecil dengan cost efektif yang diperhitungkan. Untuk bisnis selanjutnya dapat menyediakan service voice dan ISDN data, seperti fax, email dan high speed internet access. Ketika sistem Broadband CDMA dapat ditambah dengan mudah dan cepat ke jaringan existing tanpa delay dan gangguan daripada instalasi kabel telepon. Koneksi ke jaringan LAN untuk email dan sharing resources sperti printer dan mesin fax dapat dikonfigurasi dengan mudah.

Sistem Broadband CDMA dapat memungkinkan operator untuk menawarkan service yang baru seperti ISDN (144 kbps), leased line dan bandwidth on demand (2 Mbps).

Broadband sangat mengurangi efek yang menyebabkan multipath fading, terutama pada kondisi yang sebenarnya, menyebarkan range dari 7 sampai 30 MHz. Dengan bertambahnya bandwidth dapat mengurangi face margin yang diharuskan sampai 3 dB jika diterapkan pada sistem narrowband. Cell station yang baru dan reuse frekuensi pada sistem CDMA dapat ditambahkan tanpa harus memodifikasi parameter-parameter cell yang lain. Dengan penyediaan bandwidth yang lebih besar oleh Broadband CDMA akan mengijinkan lebih dari pemakai per channel, tetapi lebih sedikit cell per geographic area. Dengan demikian akan lebih simpel prosedur manajemen network.

Cell-cell pada Broadband CDMA dapat dengan mudah diaplikasikan di daerah urban, suburban atau rural dimana kepadatan pelanggan berbeda. Broadband CDMA menggunakan teknik pengkodean suara seperti pada jaringan publik (32 ADPCM dan 64 PCM)
Kemungkinan B-CDMA di Indonesia
Jika dipakai sebagai sistem selular maka B-CDMA sudah memasuki generasi ke tiga pada aplikasi IMT 2000 (International mobile telecommunications system). Teknologi ini akan memasuki pasar pada tahun 2000.

Sistem ini berbeda dengan sistem CDMA pita sempit (narrow band) dan sedang dikembangkam di Indonesia oleh PT Komselindo yang kini sebagai operator AMPS (Advance Mobile Phone System). Ia juga berbeda dengan D-AMPS (Digital-AMPS) yang distandarkan pada IS-136. Tetapi DAMPS atau GSM akan dengan mudah migrasi ke B-CDMA.

CDMA pita lebar sedang dicoba pada frekuensi 2 GHz, ia bisa menyediakan layanan internet yang di PT TELKOM disebut dengan PASOPATI dan multimedia .

Percobaan-percobaan yang sudah dilakukan, antara lain oleh NTT DoCoMo dari Jepang yang akan segera menerapkan teknologi W-CDMA (Wideband code division multiple access) pada tahun 2000 di gelombang 5 MHz. W-CDMA merupakan sebutan untuk B-CDMA di Jepang.

Yang menjadi pesaing utama dari B-CDMA adalah teknologi TD-CDMA (Time Diivision-Code Division Multiple Access. Jika TDMA membagi-bagi frekuensi secara vertikal, sementara CDMA membaginya secara horisontal, maka TD-CDMA lebih hemat lagi sebab dapat memotong-motong frekuensi lebih kecil lagi.

Pada pertemuan penyelenggara seluler dan administrator se-Asia Pasifik di forum Asia Pasific Interest Group (APIG), GSM MoU ketujuh belum sepakat terhadap pilihan Wide Band atau Broadband CDMA yang akan menjadi trend teknologi seluler GSM generasi ke tiga pada abad 21 mendatang. Kendati begitu Indonesia merekomendasi WB-CDMA sebagai pilihan ketimbang TD-CDMA yang dianggap futuristic. Apalagi Jepang melalui NTT DoCoMo turut terlibat bersama Ericsson dan Nokia dalam pengembangan sistem WB-CDMA.

Generasi ketiga berupa CDMA pita lebar bukan merupakan generasi seluler yang terakhir. Generasi berikut akan muncul pada dasawarsa pertama abad 21, yang akan lebih canggih dalam menyediakan layanan, dibanding generasi sebelumnya. Yang jelas siklus tiap generasi semakin pendek yang selain menguntungkan pengguna seluler sekaligus juga merugikannya. Keuntungannya, pelanggan bisa mendapatkan apa saja layanan yang diinginkannya, tetapi ruginya barang yang digunakan akan berusia pendek. Kerugiannya lagi jika frekuensi dan operator yang ditunjuk berbeda dengan yang sebelumnya. q

Oleh : Gunadi Dwi Hantoro
Penulis adalah alumnus STTTELKOM, dan bergabung dengan DivRisTI bidang ANW lab. Jarlokar sejak tahun 1996. Aktivitas saat ini diantaranya adalah memutakhirkan spek teknis WLL.

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