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Topic: Frequency division duplex

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Frequency division multiplexing

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	Crystal and frequency control glossary - F
		In frequency modulation, the absolute difference between (a) the maximum permissible instantaneous frequency of the modulated wave or the minimum permissible instantaneous frequency of the modulated wave and (b) the carrier frequency.
		In frequency modulation, the frequency of the carrier wave is varied in such a way that the change in frequency at any instant is proportional to another signal that varies with time.
		The transfer of signals occupying a specified frequency band, such as a channel or group of channels, from one portion of the frequency spectrum to another, in such a way that the arithmetic frequency difference of signals within the band is unaltered.
	www.icmfg.com /crystalglossaryf.html (1104 words)

	Quartz Crystals and Oscillators, Commercial Space and Industrial Applications
		The frequency vs. temperature curve is a sine with the inflection temperature at ~ +52"C. This crystal operates in the thickness shear mode.
		Nonlinear distortion characterized by the appearance, in the output of a device, of frequencies that are linear combinations of the fundamental frequencies and all harmonics present in the input signals.
		The frequency vs. temperature curve is a sine with the inflection temperature at ~ +78°C. This crystal operates in the thickness shear mode.
	www.frequencymanagement.com /glossary.html (9653 words)

	Duplex (telecommunications) - Wikipedia, the free encyclopedia
		Duplex systems are employed in nearly all communications networks, either to allow for a communication "two-way street" between two connected parties or to provide a "reverse path" for the monitoring and remote adjustment of equipment in the field.
		Time division duplex has a strong advantage in the case where the asymmetry of the uplink and downlink data speed is variable.
		Frequency division duplex is much more efficient in the case of symmetric traffic.
	en.wikipedia.org /wiki/Duplex_(telecommunications) (701 words)

	Time-Division Duplex CDMA Communications
		In the simulations of [17], the FDD mode power control bits are transmitted on average every 500 µs for a total of 2000 b/s or 6.7 percent reduction in data transmission efficiency.
		In FDD systems, the receiver in both the base station and the mobile unit must be equipped with a sufficient number of correlators and must estimate the channel impulse response.
		Frequency utilization efficiency can be also much higher in TDD systems, especially when the operation frequencies are allocated in one single band, as is the case with system operating in the Industrial, Scientific, and Medical (ISM) band.
	www.comsoc.org /pci/private/1997/apr/Esmailzadeh1.html (4148 words)

	Duplex
		In communications, duplex means "two-way" when referring to communications channels.
		Time division duplex (TDD) is the application of Time division multiple access to separate outward and return signals
		Frequency division duplex (FDD) is the application of Frequency division multiple access to separate outward and return signals
	www.ebroadcast.com.au /lookup/encyclopedia/fu/Full-duplex.html (120 words)

	TDD and FDD in WiMAX (IEEE 802.16) network
		Duplexing refers to the way downlink and uplink data is arranged in a two-way wireless transmission.
		FDD is suitable for bi-directional voice service since it occupies a symmetric downlink and uplink channel pair.
		FDD is inefficient for handling asymmetric data services since data traffic may only occupy a small portion of a channel bandwidth at any given time.
	www.conniq.com /WiMAX/tdd-fdd.htm (328 words)

	Full duplex allows simultaneous transmission in both directions (Site not responding. Last check: 2007-10-13)
		Full duplex refers to a communications device or channel that is capable of simultaneous transmission in both directions.
		One of the advantages of using switches rather than hubs on a LAN (local area network) is that the former allow full duplex operation, and thus can effectively double bandwidth as compared with the latter, which only allow half-duplex operation.
		Duplexing refers to the dividing of forward and reverse communication channels on the same physical communications medium.
	www.bellevuelinux.org /full_duplex.html (163 words)

	EETimes.com - Fixed wireless in an unlicensed band
		Frequencies 10 MHz or greater above or below the band edge must be attenuated by a factor of at least 50 dB.
		Frequency spacing refers to the actual bandwidth space that is allocated for every channel out of the total spectrum.
		If multiple FDD operators use the band and access points are not co-located, to reduce system cost, they will be separated by a guard band, enabling all terminals to use the same filter (diplexor).
	www.eetimes.com /story/OEG20010604S0075 (2006 words)

	UTRAN frequency mapping
		According to "WARC-92 frequencies for IMT-2000" resolution: "The bands 1885-2025 MHz and 2110-2200 MHz are intended for use, on a worldwide basis, by administrations wishing to implement International Mobile Telecommunications-2000 (IMT-2000).
		Carrier frequencies are designated by a UTRA Absolute Radio Frequency Channel Number (UARFCN).
		Decided that the frequency bands 1525 - 1544, 1545 - 1559, 1610 - 1626.5, 1626.5 - 1645.5, 1646.5 - 1660.5 and 2483.5 - 2500 MHz may be used for the satellite component of IMT-2000, as well as the bands 2500 - 2520 MHz and 2670- 2690 MHz, depending on market developments
	www.umtsworld.com /technology/frequencies.htm (315 words)

	Addressing the Risk of EMC Problems with Mobile Radio Transmitters
		Table III gives the characteristic frequencies of several system parameters, including the beat-like modulation that occurs when multiple transmitters are used in the vicinity of a piece of equipment.
		The characteristic frequencies of the system that lead to amplitude modulation of the signal are particularly important because these are more likely to cause EMC problems than phase-modulation effects.
		The frequency range for the standards is generally 30 or 80 MHz to 1 GHz, which covers the TETRA and GSM900 bands.
	www.ce-mag.com /archive/2000/sepoct/flintoft.html (3396 words)

	GaN Education Center - Glossary
		Because capacity, or even maximum speed, is generally dependent on the frequency range available, the 'bandwidth' (i.e., the width of a frequency band) usually has the same meaning as the maximum transmission speed available to a subscriber.
		Frequency Division Duplex: First variation of W-CDMA to be standardized and will appear commercially for the first time in Japan, mid 2001
		The frequencies band assigned to GSM is 900-1800 MHz.
	www.nitronex.com /education/glossary.html (2695 words)

	Interdigital - Glossary
		Frequency equals the number of complete cycles of current occurring in one second.
		Full duplex operation by using a pair of frequencies, one for transmission and one for reception.
		A method of radio transmission that allows a large number of users to share access to a group of radio frequency channels without interference by assigning specific frequencies within the group of frequencies to each user.
	www.interdigital.com /glossary.jsp?key=F (160 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.
		The terminology “multiple access” implies the sharing of the resource amongst users, and the “frequency division” describes how the sharing is done: by allocating users with different carrier frequencies of the radio spectrum.
		In FDMA the given Radio Frequency (RF) bandwidth is divided into smaller frequency bands called subdivisions.
	en.wikipedia.org /wiki/Frequency-division_multiple_access (414 words)

	Agilent \| Wireless \| Wireless Dictionary (Site not responding. Last check: 2007-10-13)
		In this practice, users are dynamically allocated a group of frequencies so that the apparent availability is greater than the number of channels.
		A type of signal fading occurring over a small group of frequencies caused by a strong multipath component at those frequencies.
		The most common is the two frequency FSK system using the two frequencies to carry the binary ones and zeros.
	wireless.agilent.com /dictionary/f.html (483 words)

	BreezeACCESS XL Broadband Wireless System
		BreezeACCESS XL is an advanced broadband wireless access solution optimized for data and voice applications and is an excellent alternative to wired connectivity in the local loop.
		By offering customers a high-speed wireless Internet platform and a full complement of options, service providers can efficiently maintain and grow their subscriber base.
		FDD and FH-CDMA Technology for robustness and immunity to interference
	www.airlinx.com /products.cfm/product/3-5-413.htm (631 words)

	[No title]
		Starting with analogue networks that employ frequency division multiple access (FDMA) with frequency division duplex (FDD), GSM and DCS have time division multiple access (TDMA) with FDD.
		Code division multiple access (CDMA) with FDD has entered the market in the form of IS-95.
		A study needs to be done to decide whether this concept is spectrally efficient as well as being convenient, or whether we should persist in deploying multimedia services in the same spectrum.
	www.isi.edu /workshop/WIRELESS-WKSHOP-AIRLIE/whitepapers/old-steele.txt (2305 words)

	C3: Smart Antennas for UMTS Frequency Division Duplex (Site not responding. Last check: 2007-10-13)
		Smart antennas is the commonly used name for a radio technology which uses both multiple antenna elements (an antenna array) and advanced signal processing at the baseband which dramatically increases the spectral efficiency (and capacity) of wireless networks.
		In this project, transceiver and terminal concepts will be studied with a view towards exploitation of the spatio-temporal nature of the mobile radio channel.
		Of major concern is the spectral coherence for FDD within 5 MHz of bandwidth.
	www.ftw.at /ftw/research/projects/ProjekteFolder/C3 (324 words)

	wirelessZONE Product Review: Texas Instruments TRF2432/36 RF Product Portfolio for Broadband Wireless
		These RF chipsets are capable of supporting Frequency Division Duplex (FDD), Half Frequency Division Duplex (HFDD) and Time Division Duplex (TDD) modes with a real interface at low IF to the data conversion subsystem.
		Supporting a range of frequencies between 2.1 - 2.7 GHz and 3.3 - 3.8 GHz, these power amplifiers provide excellent output third order intercept point (OIP3) of 45dBm or better, enabling the support of complex OFDM (orthogonal frequency division multiplexing) signals.
		The maximum current drain (3.3 V rail) is 10 µA. In standby mode the oscillator is running with the REF OUT buffer active (at the crystal frequency), the registers are active and the serial port is active -- typical current drain is 10 mA.
	www.analogzone.com /hfp_0606.htm (1197 words)

	WCDMA TX Theory and Measured Results from Maxim's WCDMA Reference Design v1.0 - Maxim/Dallas
		Usually defined as the ratio of the average power in the adjacent frequency channel (or offset) to the average power in the transmitted-frequency channel, ACPR describes the amount of distortion due to nonlinearities in the transmitter hardware.
		Frequency Error: the difference between specified and actual carrier frequencies.
		A large frequency error degrades transceiver performance by causing adjacent-channel interference and poor detection accuracy.
	www.maxim-ic.com /appnotes.cfm?an_pk=3043 (1828 words)

	Wave Report \| 802.16 Tutorial
		The MAC supports frequency-division-duplex (FDD) and time-division-duplex (TDD), as well as real-time adaptive modulation and coding.
		The 802.16a standard also specifies three possible modulations: single carrier, 256 OFDM, and orthogonal frequency division multiple access (OFDMA).
		The lower frequencies make non-line of sight a possibility, which can also be helped by OFDM's ability to handle multipath signals.
	www.wave-report.com /tutorials/ieee80216.htm (499 words)

	The Many Flavors of OFDMA
		Orthogonal Frequency Division Multiplexing (OFDM) is a technique for transmitting large amounts of digital data over a radio wave The technology works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver.
		Short for Orthogonal Frequency Division Multiplexing, an FDM modulation technique for transmitting large amounts of digital data over a radio wave.
		OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver.
	www.webopedia.com /DidYouKnow/Computer_Science/2005/OFDMA.asp (1743 words)

	Printer Friendly Version
		To give the broadband market a boost, Texas Instruments (Dallas, TX) recently introduced three RF chip sets at various frequencies: the TRF11xx chip set at 2.5 GHz, the TRF12xx chip set at 3.5 GHz, and the TRF24xx chip set at 5.8 GHz.
		The operating frequency of the TRF112x chip set ranges from 2.3 to 2.7 GHz.
		The TRF11233 and TRF1223 support a range of frequencies between 2.1 and 2.7 GHz and from 3.3 to 3.8 GHz, respectively.
	www.mwrf.com /Articles/Print.cfm?ArticleID=10923 (805 words)

	Untitled Document
		The CDMA-2000 is designed to be a wideband synchronous inter-cell CDMA based network using the frequency-division duplex (FDD) mode and is backward compatible with the existing CDMA-One (IS-95).
		The UWC-136 is envisioned to be an asynchronous inter-cell TDMA based system that permits both frequency-division duplex (FDD) and time-division duplex (TDD) modes.
		The WIMS is planned to be a wideband asynchronous inter-cell CDMA based system using the frequency-division duplex (FDD) operation and is compatible with ISDN.
	www.uic.edu /classes/ece/ece434/chapter_file/chapter6.htm (1683 words)

	Axxcelera Broadband Wireless - A Data Networking Solutions Company
		The ExcelMax UltraLite is a Point to Multipoint (PMP) single sector base station designed to operate in the 3.3-3.8 GHz spectrum and supports a Full FDD (Frequency Division Duplex) architecture.
		Axxcelera’s ExcelMax HD-FDD/TDD CPE is a Point to Multipoint (PMP) CPE designed to operate in the 3.3-3.8 GHz spectrum and supports a Half Duplex FDD (Frequency Division Duplex) or a TDD (Time Division Duplex) architecture.
		Axxcelera’s ExcelMax Indoor CPE is a low cost, self-installable Point to Multipoint (PMP) CPE designed to operate in the 3.3-3.8 GHz spectrum and supports a Half Duplex FDD (Frequency Division Duplex) or a TDD (Time Division Duplex) architecture.
	www.axxcelera.com /online/products.php (1475 words)

	Definitions
		This enables reception of signals that were originally overlapping in frequency and time.
		In addition, DCS 1800 operates at a higher frequency range where there is typically more bandwidth available than at the 900 MHz, allowing for higher subscriber density and traffic capacity
		Modulation produced by varying the frequency of the carrier in sympathy with the amplitude for the message signal
	www.ou.edu /engineering/emc/definitions.html (574 words)

	TI introduces RF transceiver ref designs for WiMAX apps
		These complete reference designs support FDD, Half Frequency Division Duplex and Time Division Duplex (TDD) modes with a real interface at a low intermediate frequency (IF) to the data conversion subsystem.
		In addition to providing a complete design for the designated frequency, each reference board can be customised for the various transceiving frequencies supported by each chipset.
		The TSW5002/3/5 can be customised for frequency ranges of 2.3 to 2.7GHz, 3.3 to 3.8GHz and 4.9 to 5.8GHz respectively.
	www.eetindia.com /ART_8800438326_1800005_33d754b320061019.HTM?from=RSS (347 words)

	TechWeb: The Business Technology Network (Site not responding. Last check: 2007-10-13)
		These complete reference designs support FDD, Half Frequency Division Duplex (HFDD) and Time Division Duplex (TDD) modes with a real interface at a low intermediate frequency (IF) to the data conversion subsystem.
		These chipsets support 4.9-5.9GHz air interface frequency band, and consist of an IF and RF transceiver.
		In addition to providing a complete design for the designated frequency, each reference board can be customized for the various transceiving frequencies supported by each chipset.
	www.techweb.com /showPressRelease.jhtml?articleID=X538806 (712 words)

	IEEE 802.16: Broadband Wireless MAN Standard (WiMAX)
		The fixed WiMax standard IEEE 802.16-2004 (also known as 802.16d) is approved by the IEEE in June 2004, which provides fixed, point-to-multi point broadband wireless access service and its product profile utilizes the OFDM 256-FFT (Fast Fourier Transform) system profile.
		The fixed WiMAX 802.16-2004 standard supports both time division duplex (TDD) and frequency division duplex (FDD) services - the latter of which delivers full duplex transmission on the same signal if desired.
		IEEE 802.16e, based on the early WiMax standard 802.16a, adds mobility features to WiMAX in the 2 to 11 GHz licensed bands.
	www.javvin.com /protocolWiMAX.html (310 words)

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