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Topic: FDMA


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In the News (Fri 24 May 19)

  
  Wikipedia: FDMA
FDMA, or Frequency Division Multiple Access, is the oldest and most important of the three main ways for multiple radio transmitters to share the radio spectrum.
In FDMA, each transmitter is assigned a distinct frequency channel so that receivers can discriminate among them by tuning to the desired channel.
TDMA and CDMA are always used in combination with FDMA, i.e., a given frequency channel may be used for either TDMA or CDMA independently of signals on other frequency channels.
www.factbook.org /wikipedia/en/f/fd/fdma.html   (134 words)

  
 FDMA - Frequency-Division Multiple Access
Single Channel Per Carrier (SCPC) is an FDMA scheme in which the input data stream is used to modulate an RF (radio frequency) carrier and assign dedicated carrier frequency to each client.
When FDMA is combined with TDMA each channel is multiplied into three.
FDMA, the Frequency Division Multiple Access, is frequency based channel multiplexing technique.
www.auditmypc.com /acronym/FDMA.asp   (570 words)

  
 What is Analog/FDMA Technology
FDMA is used exclusively for analog cellular systems, even though in theory FDMA can also be used with digital.
FDMA analog transmissions are the least efficient cellular networks since each analog channel can only be used one user at a time.
Not only are these FDMA channels larger than necessary given modern digital voice compression, but they are also wasted whenever there is silence during a cell phone conversation.
www.cellphonecarriers.com /analog-fdma.html   (285 words)

  
 FDMA, TDMA, CDMA, GSM explained
In this paper, the author presents a short history of mobile wireless telephony with an emphasis on the relevant air interface technologies.
FDMA, TDMA, and CDMA are put in perspective as the wireless networks evolved from the first generation to the second.
FDMA was the first allocation method and it is the easiest to understand.
www.celusion.com /whitepapers/fdma_tdma_cdma.htm   (2421 words)

  
 Power amplifier and power amplification method - Patent 5546051
Both the FDMA and TDMA systems require a power amplifier having the same AC output power of 1.5 W. 6 is a graph showing a typical example of input/output characteristics and power added efficiency in accordance with a conventional power amplifier of a dual-mode transmitter produced is for use in Japan.
The power added efficiency in the FDMA mode is approximately 60% in a 1.5 W output condition, while the power added efficiency in the CDMA mode is approximately 80% in a 0.5 W output condition.
FDMA) and to select 6.0 V when the modulation mode is a digital type (i.e.
www.freepatentsonline.com /5546051.html   (2820 words)

  
 TDMA/FDMA/CDMA hybrid radio access methods - Patent 5566168
An alternative to the analog implementation of the FDMA receiver bank is to digitize the entire composite signal and to process it digitally to separate the individual FDMA signals.
Mobiles in the same region of the earth use different FDMA channel frequencies on the uplink and according to the invention do not transmit during their received timeslots on the TDM downlink.
When uplink FDMA channels are associated with corresponding downlink TDMA timeslots, the use of a three-to-one time re-use pattern on the downlink as disclosed above automatically gives rise to a three-to-one frequency re-use pattern on the uplink, thus achieving separation of signals.
freepatentsonline.com /5566168.html   (8063 words)

  
 What is FDMA? - a definition from Whatis.com - see also: frequency division multiple access   (Site not responding. Last check: 2007-10-06)
- FDMA (frequency division multiple access) is the division of the frequency band allocated for wireless cellular telephone communication into 30 channels, each of which can carry a voice conversation or, with digital service, carry digital data.
FDMA is a basic technology in the analog Advanced Mobile Phone Service (AMPS), the most widely-installed cellular phone system installed in North America.
FDMA is also used in the Total Access Communication System (TACS).
searchnetworking.techtarget.com /sDefinition/0,,sid7_gci213959,00.html   (215 words)

  
 IEC: Local Multipoint Distribution System (LMDS)
With FDMA and TDMA access links, whether downstream or upstream, there are a number of factors that affect their efficiency and usage.
In this case, FDMA access links make sense, because the user is paying for and receiving dedicated bandwidth over the wireless access system as well as over the network infrastructure.
FDMA link is always on, regardless of whether or not the user sends data.
www.iec.org /online/tutorials/lmds/topic03.html   (769 words)

  
 Frequency-division multiple access - Wikipedia, the free encyclopedia
Frequency Division Multiple Access or FDMA is an access technology that is used by radio systems to share the radio spectrum.
In FDMA the given Radio Frequency (RF) bandwidth is divided into smaller frequency bands called subdivisions.
The first FDMA demand-assignment system for satellite was developed by COMSAT for use on the Intelsat series IVA and V satellites.
en.wikipedia.org /wiki/FDMA   (397 words)

  
 How Does A FDMA Cell Phone Work? (via CobWeb/3.1 planetlab2.cs.virginia.edu)   (Site not responding. Last check: 2007-10-06)
FDMA is an abbreviation that stands for Frequency Division Multiple Access, and this is a description of one way of using cell phones that could actually carry digital information if other better ways were not used instead, so it remains as the standard for cellular analog.
The cellular telephone system works by dividing up a geographical area into multiple smaller sections known as cells, each of which are perceived as taking on the shape of a hexagon over the area of about 10 square miles, and fit neatly together like a honeycomb in a bee hive.
So with FDMA cellular analog each cell phone carrier has 56 voice channels per cell at any one time for cellular customers to use their cell phones simultaneously; and each transmitting cell frequency has a separation of about 45 MHz from its partner receiving frequency, to prevent them from interfering with one another.
www.cell-phones-n-plans.com.cob-web.org:8888 /25377-fdma-cell-phone.html   (609 words)

  
 [No title]
The channel therefore is closed to other conversations until the initial call is finished, or until it is handed-off to a different channel.
A ìfull-duplexî FDMA transmission requires two channels, one for transmitting and the other for receiving.
FDMA divides the 25-MHz bandwidth into 124 carrier frequencies of 200 KHz each.
www.emory.edu /BUSINESS/et/552fall2003/3G/technology.htm   (642 words)

  
 PR Leap: FDMA presents "Hispanic Marketing: One Size Does Not Fit All: Understanding the Nuances, Distinctions, and ...
The meeting is open to the public with registration and networking beginning at 11:30 am followed by the lunch and presentation at noon.
The FDMA (www.fdma.org) has nearly 200 members, including catalogers, Internet retailers, financial services providers, publishers, book and music clubs and retail stores.
FDMA luncheon meetings are typically held on the third Thursday of each month at the Westin Hotel in Fort Lauderdale.
www.prleap.com /pr/34859   (490 words)

  
 Howstuffworks "How Cell Phones Work"
FDMA separates the spectrum into distinct voice channels by splitting it into uniform chunks of bandwidth.
To better understand FDMA, think of radio stations: Each station sends its signal at a different frequency within the available band.
While it is certainly capable of carrying digital information, FDMA is not considered to be an efficient method for digital transmission.
www.howstuffworks.com /cell-phone2.htm   (1213 words)

  
 ELEC301: Code Division Multiple Access (CDMA)
FDMA divides the given spectrum into channels by the frequency domain.
TDMA enhances FDMA by further dividing the spectrum into channels by the time domain as well.
Unlike FDMA and TDMA, CDMA transmission does not work by allocating channels for each phone call.
www.owlnet.rice.edu /~elec301/Projects01/cdma/compare.html   (235 words)

  
 Swimming upstream
FDMA proponents cite the simplicity of the technology.
FDMA does not pose that risk because every channel has its own frequency, he says.
A matter of perspective One major advantage to FDMA is that it allows the spectrum to be more "finely sliced" than TDMA does.
telephonyonline.com /mag/telecom_swimming_upstream_2   (3617 words)

  
 [No title]   (Site not responding. Last check: 2007-10-06)
Direct Sellers are not bound directly by the Code, but shall be required by their companies to adhere to it or to rules of conduct meeting its standards as a condition of membership in the companys distribution systems.
Direct Selling is the marketing of consumer products directly to consumers generally in their homes or the homes of others, at their workplace and other places away from permanent retail locations, usually through explanation or demonstration of the products by a Direct Seller.
With termination of its membersip in the FDMA, a company is no longer bound by the Code, the provisions of which remain applicable to events or transactions occurring during the time a company was a member of the FDMA.
www.ssml-fdma.fi /english/main_english_rules2.html   (1634 words)

  
 IEC: Local Multipoint Distribution System (LMDS)
In the previous calculations it was assumed that the FDMA channel bandwidth was 5 MHz.
Therefore, 64—QAM FDMA access is only useful when the dense data-rate customers are close to the base station site.
As in the case of the earlier FDMA example for data rate, 20,000 DS—0 lines per sector is excessive with respect to the coverage area of these LMDS systems.
www.iec.org /online/tutorials/lmds/topic05.html   (768 words)

  
 Summer FDMA Direct Marketing Tour, July 30, 1996   (Site not responding. Last check: 2007-10-06)
The FDMA summer tour complements the annual direct marketing conference to be held February 5-8, 1997 in Dover, Delaware.
Virginia FDMA members voted to conduct their conference jointly with other Mid-Atlantic states.
FDMA reserves the right to cancel the tour for lack of participation.
www.ext.vt.edu /news/periodicals/fmu/1996-06/aaec-316.html   (265 words)

  
 FDMA   (Site not responding. Last check: 2007-10-06)
FDMA divides an area in the radio spectrum into multiple channels allowing many radio transmitters to share the radio spectrum.
Transmitters are assigned specific channels in the radio spectrum.
Each channel is at a slightly different frequency.
www.comptechdoc.org /independent/networking/terms/fdma.html   (37 words)

  
 PR Leap: Direct Marketer to Share with the FDMA How He Generated 33% Response, Key Data and 30% More Sales by Doing ...
Register by contacting Laura Silverman, FDMA Executive Director at 954-724-3662 or info@fdma.org.
The FDMA has nearly 200 members, including catalogers, Internet retailers, financial services providers, publishers, book and music clubs and retail stores.
The FDMA was a chapter of the national Direct Marketing Association from late 2002 until August 1, 2005, when it once again became an independent organization.
www.prleap.com /pr/24470   (751 words)

  
 [No title]   (Site not responding. Last check: 2007-10-06)
FDMA systems are the least efficient cellular system since each analog channel can only be used by one user at a time.
FDMA is algorithmically and from hardware point of view simple to develop.
Conclusion CDMA systems are the latest on the market when compared to FDMA and TDMA and eclipses both in terms of all factors like bandwidth usage, clarity, capacity coverage etc. CDMA technologies providing such a large advantages are now widely coming into usage in the market.
www.cs.wright.edu /~jstephen/sankaranarayanan.doc   (2952 words)

  
 FDM: Frequency Division Multiplex and FDMA
Wavelength Division Multiplex (WDM) and Frequency Division multiplex (FDM) are both based on the same principles but WDM applies to digitized wavelengths of light in optical fiber while FDM is used in analog transmission such as twisted pair telephone line, cable access, cellular, radio and TV communications.
FDMA analog transmissions are the least efficient networks since each analog channel can only be used one user at a time.
Not only are these FDMA channels larger than necessary given modern digital compression, but they are also wasted whenever there is silence during communication.
www.networkdictionary.com /telecom/fdm.php   (367 words)

  
 FMOD transceivers including continuous and burst operated TDMA, FDMA, spread spectrum CDMA, WCDMA and CSMA ...
FBPSK modem is shown to meet the IEEE 802.11 specified spectral direct sequence spread spectrum mask (−30 dB point) for wireless LAN, and leads to an output power gain of 6.5 dB over conventional BPSK modems.
The cross-coupled quadrature FMOD structure is also suitable for continuous mode and for burst operated TDMA, FDMA, CDMA, WCDMA and CSMA Frequency Modulation Quadrature AM (QAM), QPSK and offset QPSK, as well as pi/4-shifted QPSK modems/processors.
Reduced modulation index Gaussian FSK (GFSK), multilevel FM and cross-coupled Quadrature Amplitude Modulated (QAM) transmitters and combinations of these modulations and corresponding coherent demodulators are disclosed.
www.delphion.com /details?pn=US22181547A1   (541 words)

  
 Cell phone review, news, specification and shopping :: cellsea.com
The oldest and simplest method for accommodating multiple simultaneous users in a band of radio frequency spectrum.
FDMA means simply dividing the band into smaller bands.
While original analog (AMPS) mobile phone systems used only FDMA, modern digital systems use FDMA to separate groups of users, and some form of CDMA and/or TDMA to separate individual users within those groups.
www.cellsea.com /java-cellsea/glossary/FDMA.htm   (96 words)

  
 The DMA - Florida Chapter | Events
The program is designed for a marketing, advertising, or communications major from the state of Florida who will have completed his or her sophomore or junior year by June 2004, and who is seriously interested in a career in direct marketing.
The FDMA SCHOLARSHIP PROGRAM consists of a $500 scholarship, membership in the Florida Direct Marketing Association and a mentor from the industry.
The FDMA TEACHING EXCELLENCE AWARD consists of an award for FDMA Outstanding Educator of the Year Award given to an educator who has demonstrated overall consistent excellence in Direct Marketing Education and Teaching Excellence Awards given to educators who have developed new and innovative approaches to Direct Marketing Education.
www.fdma.org /scholarship.asp   (214 words)

  
 Florida Direct Marketing Association Hosts the “2006 Annual Direct Marketing Summit and Expo” on Sept. 21, ...   (Site not responding. Last check: 2007-10-06)
Fort Lauderdale, FL (PRWEB via PRWeb) August 28, 2006 –- Innovate: Integrate is the theme for this year’s Direct Marketing Summit for Florida Direct Marketing Association’s (FDMA) annual summit conference and exposition being held Thursday, September 21, 2006 at the Westin Hotel on Cypress Creek Road and I-95 in Fort Lauderdale from 8:30 a.m.
The combined cost to attend is $79 for members, $99 for non-members and includes continental breakfast and full lunch, trade show expo, and plenty of opportunities to network and learn from three expert speakers.
For more information, contact Keith Fletcher, FDMA Board President, at 786-357-3275.
www.prweb.com /releases/2006/8/prweb429663.htm   (729 words)

  
 FMOD transceivers including continuous and burst operated TDMA, FDMA, spread spectrum CDMA, WCDMA, and CSMA (US6445749)
FBPSK modem is shown to meet the IEEE 802.11 specified spectral direct sequence spread spectrum mask (-30 dB point) for wireless LAN, and leads output power gain of 6.5 dB over BPSK modems.
The Crosscoupled Quadrature Structure is also suitable for continuous mode and for burst operated TDMA, FDMA, CDMA, WCDMA and CSMA.
US20020181547A1 issued 2002-12-05 FMOD transceivers including continuous and burst operated TDMA, FDMA, spread spectrum CDMA, WCDMA and CSMA
www.delphion.com /details?pn=US06445749__   (577 words)

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