Issue: April 2010
TD-SCDMA in China: A Really Big Thing
When a central government makes the rules, brooks no opposition, and has no democratic process to "get in the way", big infrastructure projects tend to get done, and fast. The Peoples Republic of China is the world's best example. If the government thinks an enormous dam or tens of thousands of miles or roads and rail lines are needed, they just get built -- and quickly.
The same is true for third-generation wireless systems, the bulk of which the government has determined will use its own homegrown technology called TD-SCDMA (Time Division Synchronous Code Division Multiple Access). It licensed China Mobile, the world's largest wireless carrier by number of subscribers, to use TD-SCDMA exclusively, while two other smaller carriers will use W-CDMA and CDMA. In 2009 alone, China Mobile deployed 90,000 TD-SCDMA base stations throughout the country and will deploy 70,000 more this year, and there are already more than 5.5 million TD-SCDMA subscribers. Based on current estimates, TD-SCDMA will rapidly become of the most widely-deployed 3G technologies in a span of only a few years, even though it was deployed from scratch and deployment has been underway for little more than a year.
From a nationalistic perspective, the government decided to develop its own 3G standard to avoid paying royalties to companies holding patents on existing technologies, although TD-SCDMA does have some advantages. Its time-division duplexing lets carriers dynamically adjust the number of time slots used by the downlink and uplink paths. TD-SCDMA also does not require paired spectrum for the downlink and uplink so spectrum allocation can be more flexible, and by using the same carrier frequency for the uplink and downlink paths, the channel characteristics are the same in both directions. But most important to the central government, it is (mostly) a Chinese invention.
Cavity Bandpass Filter for Outdoor WiFi
The Model AB2436B480 is a ruggedized, weatherproof cavity bandpass filter for outdoor IEEE-802.11b/g WiFi installations that has excellent harmonic rejection, handles up to 50 W of RF input power, and is extremely selective. The filter has a center frequency of 2436.5 MHz, 3-dB bandwidth of 70 MHz, typical insertion loss of 0.9 dB, return loss of 18 dB min, harmonic rejection greater than 80 dB, and handles 50 W of RF input power. The AB2436B480 has an operating temperature range of -40 to +85 C and measures 4.8 x 2.8 x 1.2 in.
A Message from Sam Benzacar
EMI Filters Keep the Noise Out
Electromagnetic interference (EMI) has always been the adversary of designers who create every type of electronic system. For practical purposes, there are an almost limitless number of sources from which this interference can be generated and keeping it out of sensitive receivers and other systems is paramount.
Fortunately, there are proven ways to maintain signal integrity when faced with EMI, one of which is the EMI filter. This type of filter has two basic elements: series impedances (usually inductors) and shunt impedances (usually capacitors). These components when configured as a lowpass filter, reduce unwanted electrical energy entering or leaving a circuit. The key challenge for an EMI filter is to maintain a high level of capacitive shunting performance at high frequencies.
Anatech offers a broad array of EMI filters for most applications that have excellent capacitive performance and other excellent characteristics as well. They can handle extremely high current (up to 400 A) and voltages up to 500 VDC. Our filters have high insertion loss from frequencies as low as 1 kHz and more than 60 db of insertion loss to 1 GHz and above. Their ability to remove high-frequency noise from very-high-current lines makes these devices an excellent choice for high-current filtering. For more information, give us at a call at (973) 772-4242 or send us an e-mail at email@example.com.
Featured EMI Filters
Three products illustrate the capabilities of our EMI filters. All have insertion loss greater than 60 dB, provide filtering from 1 kHz to 1 GHz, are housed in a bolt-on/bulkhead enclosure, have an operating temperature range of 55 to +125 C at 98% humidity, withstand shock of 30 g (11 ms), and have an MTBF of 500,000 hr. The Model HF250EMI125 handles 250 A and RF current of 10 A RMS, has capacitance up to 22 µF, and measures 4 x 1.25 x 0.78 in. Our Model HF50EMI122 handles 50 A and RF current of more than 10 A RMS, has capacitance of 4.7 µF, and measures 2.1 x 0.94 x 0.45 in.
All three filters and the others in our EMI filter line are available from our Web store, www.AMCrf.com.
Anatech Electronics will be exhibiting at the 2010 IEEE MTT-S IMS show from May 25-27 in Anaheim, California at the Anaheim Convention Center.
Come Visit us at booth #1344!
If you would like to obtain a free pass please contact us!
If you have any questions regarding our products, or comments on our newsletter, please email us at: firstname.lastname@example.org
3-D TV: The Next Big Thing?
Watching television in three dimensions seems like a dream come true, and TV manufacturers are hoping we all agree. 3-D TV seems to have risen from an interesting idea to a main thrust of the consumer electronics industry in less than a year. However, the concept has been around in theaters since the 1950s, but has never caught on for a lot of the same reasons consumers ought to consider today as the first 3-D TVs hit the market.
Making three dimensional viewing watchable is extraordinarily difficult to achieve in a consumer device, thanks to the enormous processing horsepower required to make it happen. There are several methods of achieving it, all of which have significant drawbacks. From the viewers' perspective, 3-D TV as it is currently implemented may give even early adopters second thoughts. So if you're considering taking the plunge into 3-D TV, we'd recommend you read an article that appeared in the April 8 issue of EDN called "Coming Soon: 3-D TV", written by Senior Technical Editor Brian Dipert. It is well researched - and pulls no punches.
We're Ready for 700 MHz! Are You?
Deployment of LTE at 700 MHz is moving fast, and with it the need for cost-effective, high-performance filtering solutions to keep interference in check and comply with FCC requirements. Anatech Electronics offers a full line of filters designed for Bands A through C, including bandpass combiners that allow a single antenna to be used for transmit and receive signals in any two bands, and weather-resistant cavity filters for tower-top mounting.
Cavity Bandpass Combiners
Cavity Bandpass Filters
When it comes to 700 MHz filter solutions, Anatech has you covered. Call us today!
Answers to last month's trivia questions
1. What California city did the last Pony Express ride end in? Sacramento
2. What's the second most populous continent? Europe
3. What's the flattest U.S. state? Florida
1. What U.S. state is the eighth largest economic power in the world?
2. What was an official language in 87 nations and territories, by 1994?
3. What South Asian city is the planet's biggest feature film producer?
Look for the answers in next month's issue!
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