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Topic: Discrete multitone modulation

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  Modulation - Wikipedia, the free encyclopedia   (Site not responding. Last check: 2007-08-08)
Modulation is the process of varying a carrier signal, typically a sinusoidal signal, in order to use that signal to convey information.
One of the three key characteristics of a signal is usually modulated: its phase, frequency or amplitude.
A device that performs modulation is known as a modulator and a device that performs demodulation is known as a demodulator.
en.wikipedia.org /wiki/Modulation   (711 words)

 Encyclopedia: Modulation
In digital modulation, the changes in the signal are chosen from a fixed list (the modulation alphabet) each entry of which conveys a different possible piece of information (a symbol).
Phase modulation (PM) is a form of modulation which represents information as variations in the instantaneous phase of a carrier wave.
Pulse-code modulation (PCM) is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code.
www.nationmaster.com /encyclopedia/Modulation   (2195 words)

 Discrete multitone modulation   (Site not responding. Last check: 2007-08-08)
In perception a discrete entity is something that can be percepted individually and not as connected to, or part of something else.
In mathematics a discrete set is a countable or countably infinite, with a cardinality less than or equal to aleph 0.
In mathematics, a discrete space is a topological space in which all sets are open.
www.serebella.com /encyclopedia/article-Discrete_multitone_modulation.html   (376 words)

 modulation   (Site not responding. Last check: 2007-08-08)
Modulation factor - Modulation factor : In amplitude modulation, the ratio of the peak variation actually used, to the maximum design variation in a given type of modulation.
Delta modulation - Delta modulation (DM): Analog-to-digital signal conversion in which (a) the analog signal is approximated with a series of segments, (b) each segment of th...
Pulse-position modulation - Pulse-position modulation is a form of signal modulation in which the message information is encoded in the temporal spacings between a sequence of signal p...
www.serebella.com /search/topic-modulation.html   (427 words)

 Modulation - Open Encyclopedia   (Site not responding. Last check: 2007-08-08)
A device that performs modulation is known as a modulator.
Where the signal is a simple low speed on-off indication, as in morse code or radioteletype (RTTY) transmission, modulation is often known as 'keying' as in the terms
Modulation is frequently used in conjunction with various channel access methods.
open-encyclopedia.com /Modulation   (227 words)

 Multitone IMD offers clearer picture of MCPA performance
The multitone signal must be configured with a notch that has hundreds of tones that represent one of the channels.
If the frequency of interest is not a discrete frequency offset, but it has a certain bandwidth, the offset will be a function not only of the frequency offset, but also of the bandwidth over which the distortion power needs to be integrated.
Generating multitone signals digitally dramatically reduces this complexity, allows pre-distortion to be used to improve dynamic range, enables an appropriate time-domain profile to be established, and creates an overall stimulus environment that is extremely realistic and repeatable, as well as highly configurable.
www.rfdesign.com /mag/radio_multitone_imd_offers/index.html   (2230 words)

 The Credence Report - Meeting Test Challenges for ADSL ICs   (Site not responding. Last check: 2007-08-08)
Discrete multitone (DMT) modulation has emerged as the dominant FDM method in ADSL.
With DMT modulation, services are provided by dividing the approximately 1.1 MHz of spectrum into 256 equally-spaced subchannels, or tones, each of which occupies 4.3125 kHz.
The DMT modulation scheme used in ADSL is based on multiple orthogonal signal components at a regular spacing.
www.credence.com /e_news/issue0703/article06-0703.html   (2364 words)

 Modulation   (Site not responding. Last check: 2007-08-08)
Modulation of pro-inflammatory cytokine activity is a plausible therapeutic target in periodontal disease.
These data indicate a functional role for 12/15LO in the modulation of oxidative reactions in the central nervous system, supporting the hypothesis that...
He called for a 1 per cent increase in the basic modulation rate in 2009, with the rate increased each year until it reaches 10 per cent.
www.wikiverse.org /modulation   (269 words)

 Orthogonal frequency division modulation : Discrete multitone modulation
An OFDM signal may be regarded as the sum of a number of individual sub-carrier signals, each modulated (typically using QAM) by its own modulating signal.
OFDM modulation and demodulation are typically (as of 2001) implemented using digital filter banks generally using the Fast Fourier Transform.
Some COFDM systems use some of the sub carriers to carry pilot signals, which are used for frequency stabilisation, as frequency shifts during the transmission using the main modulation/demodulation process transform into bit errors in the decoded data.
www.fastload.org /di/Discrete_multitone_modulation.html   (544 words)

 RF transceiver multitone analysis
When combined with the earlier stated speedups for various multitone analyses, these improvements in Monte Carlo simulation can mean the difference between a design that is not fully characterized in the nominal condition and one that is fully understood over the process space.
Their spectrum may represent transient signals or pseudo-random digital modulation with their continuous spectrum, or they may also include periodic signals with their discrete spectral lines, such as those representing the intermodulation products from a mixer or amplifier under multitone sinusoidal excitation.
This technique considers a modulated signal as a combination of low-frequency dynamic (the envelope of the carrier or the modulation) and a high frequency dynamic (the carrier), which are analyzed separately and then merged together.
www.rfdesign.com /mag/radio_fast_multitone_analysis/index.html   (2297 words)

 ELEN E6768: Topics in Telecom: Modern Digital Modulation Technologies   (Site not responding. Last check: 2007-08-08)
He is currently working on digital modulation techniques and multiple access techniques for both terrestrial and satellite mobile wireless communications systems.
Discrete Multitone (DMT) is presently being used in the ADSL, VDSL and G.Lite systems.
CPM modulations are constant-envelope modulations which allow the use of non-linear power-efficient transmitter amplifiers in cellular and space communications.
www.cvn.columbia.edu /Courses/Summer2005/ELENE6768-2.html   (993 words)

 Citations: Discrete multitone modulation for transmission on the cable television network - Jacobsen, Chow, Cio ...   (Site not responding. Last check: 2007-08-08)
Jacobsen, P. Chow, and J. Cio, \Discrete multitone modulation for transmission on the cable television network," in IEEE 802.catv Committee Contribution Number 94-024, (Orlando, FL), July 1994.
A common subchannel modulation method is quadrature amplitude modulation.
DMT is a form of multicarrier modulation in which the original spectrum of the input signal is spread over numerous bands, called subchannels.
citeseer.ist.psu.edu /context/1867800/0   (198 words)

 MODULATIE   (Site not responding. Last check: 2007-08-08)
In de telecommunicatie beschrijft modulatie een aantal technieken voor het encoderen van informatie op een draaggolf, meestal een sinussignaal.
Het apparaat dat de modulatie verzorgt is een modulator.
Als OFDM wordt gebruikt in combinatie met kanaalcodeertechnieken, wordt het omschreven als Coded orthogonal frequency division modulation (COFDM).
www.thumpershollow.com /encyclopedia/M/Modulatie   (148 words)

 Orthogonal frequency-division multiplexing   (Site not responding. Last check: 2007-08-08)
Orthogonal frequency-division multiplexing (OFDM), also sometimes called discrete multitone modulation (DMT), is a transmission technique based upon the idea of frequency-division multiplexing (FDM) where multiple signals are sent out at different frequencies.
This, coupled with the use of advanced modulation techniques on each component, results in a signal with high "orthogonality"—resistance to interference.
An OFDM baseband signal is the sum of a number of orthogonal sub-carriers, with data on each sub-carrier being independently modulated commonly using some type of quadrature amplitude modulation (QAM) or phase-shift keying (PSK).
www.omniknow.com /common/wiki.php?in=en&term=Discrete_multitone_modulation   (1509 words)

 Discrete multitone modulation   (Site not responding. Last check: 2007-08-08)
Orthogonal frequency division modulation (OFDM, also called orthogonal frequencydivision multiplexing) is a modulation technique for modulating(encoding) digital information into an analog carrier electromagnetic (e.g.
The benefits of using OFDM are that it is easy to filter out noise (if a particular range of frequencies suffers from interference, the carriers within that range canbe disabled or made to run slower), and that the upstream and downstream speeds can be varied by allocating either more or fewercarriers for each purpose.
When OFDM is used in conjunction with channel coding techniques, itis described as coded orthogonal frequency division modulation (COFDM).
www.therfcc.org /discrete-multitone-modulation-43894.html   (778 words)

 discrete multitone - a Whatis.com definition - see also: DMT   (Site not responding. Last check: 2007-08-08)
Discrete multitone (DMT) is a method of separating a Digital Subscriber Line (DSL) signal so that the usable frequency range is separated into 256 frequency bands (or channels) of 4.3125 kHz each.
Within each channel, modulation uses quadratude amplitude modulation (QAM).
Find white papers, products and vendors related to discrete multitone.
searchnetworking.techtarget.com /sDefinition/0,,sid7_gci748455,00.html   (178 words)

 Modulation   (Site not responding. Last check: 2007-08-08)
A biotechnical company engaged in research and commercial development of immune modulation therapies for the treatment of cardiovascular, neurological, and other chronic inflammatory diseases.
Research in the modulation of synaptic function by hormones and their non-genomic action in the amphibian neuromuscular junction, at the Department of Physiology, UCC, Bayamón, PR.
Handy list of transmitters, transceivers and amplifiers and listings for which tubes are used in their final stages for RF amplification and modulation.
www.omniknow.com /common/wiki.php?in=en&term=Modulate   (1560 words)

 dmt   (Site not responding. Last check: 2007-08-08)
DMT is a TLA which may stand for
Discrete monitor timing (a VESA standard for computer displays)
This is a disambiguation page; that is, one that points to other pages that might otherwise have the same name.
www.yourencyclopedia.net /dmt.html   (123 words)

 Orthogonal Frequency Division Modulation   (Site not responding. Last check: 2007-08-08)
One interesting example is a 4G wireless communications link using Orthogonal Frequency Division Multiplexing (OFDM) modulation and MIMO antenna technology.
Orthogonal frequency division modulation (OFDM, also called orthogonal frequency division multiplexing) is a modulation technique for modulating (encoding) digital information into an analog carrier electromagnetic (e.g.
OFDM modulation and demodulation are typically (as of 2001) implemented using digital filter banks generally using the Fast Fourier Transform(FFT).
www.wikiverse.org /orthogonal-frequency-division-modulation   (838 words)

 NC Exchange - Articles VDSL
Currently, the standard VDSL uses up to 4 different frequency bands, two for upstream (from the client to the telco) and two for downstream.
The standard modulation technique is either QAM (Quadrature amplitude modulation) or DMT (Discrete multitone modulation) which are not compatible, but have similar performance.
The current mostly used technology is QAM (the same technology used in cable modems).
www.ncexchange.org /68_Articles_VDSL.html   (156 words)

 ADSL Modulation Methods   (Site not responding. Last check: 2007-08-08)
ANSI standard [4] describes a basic ADSL system which uses DMT (Discrete Multitone) modulation.
In this chapter the DMT modulation method is described.
Modulation by the inverse discrete Fourier transform (IDFT)
www.cs.tut.fi /tlt/stuff/adsl/node21.html   (51 words)

 Discrete Multitone (DMT) vs. Carrierless Amplitude/ Phase (CAP) Line Codes from Analog Devices White Papers at ...
Discrete Multitone (DMT) vs. Carrierless Amplitude/ Phase (CAP) Line Codes
This paper describes why discrete multitone (DMT) modulation is the best choice for asymmetric digital subscriber lines (ADSL), and why the international experts and standards bodies have chosen DMT.
In terms of communications speed, bandwidth efficiency, spectral compatibility, performance, robustness and power consumption, DMT is a better choice than alternative single-carrier technologies.
whitepapers.silicon.com /0,39024759,60000493p-39000383q,00.htm   (611 words)

 amplitude modulation on Encyclopedia.com   (Site not responding. Last check: 2007-08-08)
BROADBAND DESIGN -- Choose Wisely Between Quadriture Amplitude Modulation and Discrete Multitone Technology for Very High Digital Subscriber Line -- The move to VDSL has many operators torn between QAM and DMT for...
(discrete multitone, carrierless amplitude phase and quadriture amplitude modulation proponents continue to market wares aggressively)
Amplitude Modulation of Pulsatile Insulin Secretion by Intrapancreatic Ganglion Neurons.
www.encyclopedia.com /html/x/x-amplitudm1od.asp   (318 words)

 Elektrorevue - Modulace DMT (Discrete MultiTone)
Ve snaze vyuzít co nejlépe jiz existující medené prístupové telefonní síte, vyuzívají tyto systémy moderní modulacní metody jako napríklad DMT (Discrete MultiTone) a CAP (Carrierless AM/PM).
Jsou to predevsím DMT (Discrete MultiTone) urcená predevsím pro prenos dat na telefonních prístupových sítích tvorených medenými kroucenými páry a umoznující adaptivní bitovou alokaci dle pomeru signál-sum, Orthogonally multiplexed Quadrature Amplitude Modulation (OQAM), Discrete Wavelet MultiTone (DWMT), Orthogonal Frequency Division Multiplexing (OFDM) pouzívaný v digitálním rozhlasovém vysílání DAB (Digital Audio Broadcasting).
V dalsích kapitolách se budeme venovat konkrétnímu systému DMT (Discrete MultiTone) a nebude-li uvedeno jinak, bude uvádena tato modulace tak, jak je uzita v systému ADSL.
www.elektrorevue.cz /clanky/01006   (8543 words)

 IEEE Journal on Selected Areas in Communications (J-SAC), Volume 13
Takis Mathiopoulos: Performance Analysis of Asymptotically Optimal Noncoherent Detection of Trellis-Coded Multi-Amplitude/-Phase Modulation Signals in Gaussian Noise and ISI Channels.
Melbourne Barton, Michael L. Honig: Optimization of Discrete Multitone to Maintain Spectrum Compatibility with Other Transmission Systems on Twisted Copper Pairs.
Stuart D. Sandberg, Michael A. annes: Overlapped Discrete Multitone Modulation for High Speed Copper Wire Communication.
www.informatik.uni-trier.de /~ley/db/journals/jsac/jsac13.html   (2491 words)

 modulation   (Site not responding. Last check: 2007-08-08)
: ''For the musical use of "modulation", see '''modulation (music)'''.''
When transmitting digital data, modulation normally involves shifting one or more properties of the carrier wave between a set of states, a process referred to as keying.
Amplitude-shift keying (ASK) and its most common form, on-off keying (OOK) ''see Amplitude modulation''
q-basic.xodox.de /modulation   (194 words)

 Telecommunications and Signal Processing Seminar   (Site not responding. Last check: 2007-08-08)
ADSL is based on discrete-multitone modulation in which multiple digital Quadrature Amplitude Modulation (QAM) signals are combined via an inverse Fourier transform and transmitted as a single signal over an ADSL line.
The inverse Fourier transform implements discrete multitone modulation.
This talk will cover the fundamentals of ADSL modems, including multicarrier modulation, cyclic prefix, channel shortening, sample synchronization, and symbol synchronization.
signal.ece.utexas.edu /seminars/dsp_seminars/99fall/arslan.html   (177 words)

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