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	Harry Nyquist Summary
		Nyquist was born on February 7, 1889, in Nilsby, Sweden.
		Nyquist developed a method to transmit pictures—a crude but working facsimile (fax) machine—in which a photographic transparency was scanned, the scanned data was converted to electric signals in proportion to the intensity of shades and tones of the image, and these signals were sent over telephone lines to a photographic negative film.
		Nyquist died in Harlingen, Texas on April 4, 1976.
	www.bookrags.com /Harry_Nyquist (984 words)

	Harry Nyquist
		Harry Nyquist (February 7, 1889 - April 4, 1976) was an important contributor to information theory.
		In 1927 Nyquist determined that an analog signal should be sampled at twice the frequency of its highest-frequency component in order to be converted into an adequate representation of the signal in digital form.
		Nyquist published his results in the paper Certain topics in Telegraph Transmission Theory (1928).
	www.ebroadcast.com.au /lookup/encyclopedia/ha/Harry_Nyquist.html (180 words)

	Spartanburg SC \| GoUpstate.com \| Spartanburg Herald-Journal (Site not responding. Last check: 2007-10-09)
		Nyquist stability criterion can now be found in all textbooks on feedback control theory.
		In 1927 Nyquist determined that the number of independent pulses that could be put through a telegraph channel per unit time is limited to twice the bandwidth of the channel.
		Nyquist lived in Pharr, Texas after his retirement, and died in Harlingen, Texas on April 4, 1976.
	www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=Harry_Nyquist (310 words)

	Information theory founders (Site not responding. Last check: 2007-10-09)
		Harry was the fourth child of eight and was born on 7 February 1889 in Nilsby, Sweden.
		Harry Nyquist came to the University of North Dakota, Grand Forks, in 1912, where he earned his Bachelor of Science in Electrical Engineering degree in 1914 and his master of Science in Electrical Engineering degree in 1915.
		Harry Nyquist (1920's) showed that to distinguish unambiguously between all signal frequency components we must sample at least twice the frequency of the highest frequency component, Figure 1.
	it-science.net /nyquist.html (2926 words)

	Nyquist plot
		A Nyquist plot is a type of graph used in signal processing in which the magnitude and phase of a frequency response are plotted on orthogonal axes.
		The Nyquist plot shows the amplification/attenuation and phase-shift of the signal in the complex plane.
		The Nyquist plot is named after Harry Nyquist, a former engineer at Bell Laboratories.
	www.ebroadcast.com.au /lookup/encyclopedia/ny/Nyquist-plot.html (168 words)

	Nyquist-Shannon sampling theorem (Site not responding. Last check: 2007-10-09)
		The theorem was first formulated by Harry Nyquist in 1928 ("Certain topics in telegraph theory") but was only formally proved by Claude E. Shannon in 1949 ("Communication in the presence noise").
		The minimum sample frequency that allows of the original signal that is 2W samples per unit distance is known the Nyquist frequency (or Nyquist rate).
		A well-known consequence of the sampling theorem that a signal cannot be both bandlimited and time-limited.
	www.freeglossary.com /Nyquist-Shannon (840 words)

	IEEE - Harry Nyquist, 1889 - 1976
		Harry Nyquist (A'39-M'47-F'52) was born on 7 February 1889 in Nilsby, Sweden.
		From 1917 to 1934 Nyquist was employed by the American Telephone and Telegraph Company in the Department of Development and Research Transmission, where he was concerned with studies on telegraph picture and voice transmission.
		After his retirement, Nyquist was employed as a part time consultant engineer on communication matters by the Department of Defense, Stavid Engineering Inc., and the W. Maxson Corporation.
	www.ieee.org /web/aboutus/history_center/biography/nyquist.html (298 words)

	Nyquist-Shannon sampling theorem : Nyquist sampling theorem
		The theorem was first formulated by Harry Nyquist in 1928 ("Certain topics in telegraph transmission theory"), but was only formally proved by Claude E. Shannon in 1949 ("Communication in the presence of noise").
		The minimum sample frequency that allows reconstruction of the original signal, that is 2W samples per unit distance, is known as the Nyquist frequency, (or Nyquist rate).
		Nyquist, "Certain topics in telegraph transmission theory," Trans.
	www.fastload.org /ny/Nyquist_sampling_theorem.html (335 words)

	Modern Control Engineering - Nyquist (Site not responding. Last check: 2007-10-09)
		Harry Nyquist was born in Nilsby, Sweden in 1889.
		This work was dependent on Nyquist's earlier theoretical analysis of noise.
		Finally, Harry Nyquist was engaged in studies of feedback amplifiers, which led to a simple method of assessing their stability, and also explained the phenomena of conditional stability.
	www.cai.cam.ac.uk /people/dmh/engineering/engineer03l/cenyquist.htm (310 words)

	Harry Nyquist Beschreibung in Library - Definition und Buch-Tipp.
		Harry Nyquist, (* 7.02 1889 in Nilsby, Schweden; † 14.04 1976 in Harlingen, Texas) war ein amerikanischer Physiker.
		Harry Nyquist wurde in Nilsby in Schweden geboren und wanderte 1907 in die Vereinigte Staaten Amerika aus.
		Nyquist publizierte seine Forschungsergebnisse 1928 unter dem Titel "Certain topics in Telegraph Transmission Theory", heute bekannt als Nyquist-Shannon Abtasttheorem.
	harry_nyquist.know-library.net (726 words)

	Nyquist–Shannon sampling theorem - Wikipedia, the free encyclopedia
		In addition to Claude Shannon and Harry Nyquist, it is also attributed to Whittaker and Kotelnikov, and sometimes simply referred to as the sampling theorem.
		Frequency components that are above the Nyquist frequency are subject to a phenomenon called aliasing, which is undesirable in most applications.
		The theorem was first formulated by Harry Nyquist in 1928 ("Certain topics in telegraph transmission theory"), but was only formally proven by Claude E. Shannon in 1949 ("Communication in the presence of noise").
	www.physics.utah.edu /~springer/phys6620/lectures/lec04_20060124/Nyquist-Shannon_sampling_theorem.htm (2932 words)

	Harry Nyquist Papers (Site not responding. Last check: 2007-10-09)
		Harry Nyquist was born February 7, 1889 in Nilsby, Sweden and emigrated to the United States in 1907.
		Nyquist was an expert and pioneer in high speed telegraphy and is best known for inventing the Nyquist diagram and Nyquist interval.
		Nyquist received many honors for his contributions in the communication and control field, including: NAE Founders' Medal of Honor (1969), the Ballantine Medal of the Franklin Institute (1960), the IEEE's Medal of Honor (1960), and the ASME Oldenburger Medal (1975).
	www.und.nodak.edu /dept/library/Collections/og1176.html (374 words)

	Nyquist rate - Wikipedia, the free encyclopedia
		In signal processing, the Nyquist rate is two times the bandwidth—but this concept has two rather different meanings: as a lower bound for the sample rate for alias-free signal sampling, and as an upper bound for the signaling rate across a bandwidth-limited channel such as a telegraph line.
		Nyquist's famous 1928 paper was a study on how many pulses (code elements) could be transmitted per second, and recovered, through a channel of limited bandwidth.
		Nyquist frequency — The Nyquist rate is defined differently from the Nyquist frequency, which is the frequency equal to half the sampling rate of a sampling system, and is not a property of a signal.
	en.wikipedia.org /wiki/Nyquist_rate (486 words)

	ProSoundWeb \| The Nyquist Plot
		The Nyquist plot can be used in sound system work, where in acoustics the real part is particle pressure and the imaginary part is particle velocity (near a boundary or in a standing wave) and in impedance measurements where the real part is the resistance and the imaginary part is the reactance.
		Note that in the diagram the cursor is set at the point where the reverse rotation begins, the cursor coordinates being indicated to the lower left of the plot.
		The Nyquist plot, as embodied in contemporary acoustic analyzers, usually computes at the bottom of the screen the values for frequency, real part, imaginary part, phase, and magnitude for a given cursor position on the screen.
	www.prosoundweb.com /install/sac/n26_4/nyquist/nyquist.shtml (707 words)

	Chapter Five: Principles of Digital Audio
		In 1928, a Swedish-born researcher for ATandT named Harry Nyquist published a paper entitled "Certain Topics in Telegraph Transmission Theory." In it, he presented a method for converting analog waveforms into digital signals for more accurate transmission over phone lines.
		He presented the concept of sampling amplitudes at a specific rate, as described on the previous page, and most importantly determined that the sampling rate would need to be at least twice the highest frequency to be reproduced.
		The frequency they produced is predictable, in that they are mirrored the same distance below the Nyquist frequency as the original was above it, at the original amplitude.
	www.indiana.edu /~emusic/etext/digital_audio/chapter5_nyquist.shtml (621 words)

	Nyquist Sampling (Site not responding. Last check: 2007-10-09)
		The Nyquist Sampling Theorem sets the fundamental limits on any system that digitizes signals, whether it be a CD player, a telecommunications system, or a CCD camera.
		The American physicist and electrical engineer Harry Nyquist proved that if the sampling is at least twice the highest spatial frequency component in the image, no distortion will occur and you can reconstruct an exact replica of the original image.
		The theorem really requires the image to be filtered (smoothed) to remove any higher frequency components; but in practice, the limitations of the optics and seeing take care of this for you.
	www.cyanogen.com /help/maximdl/Nyquist_Sampling.htm (279 words)

	Amazon.com: "Harry Nyquist": Key Phrase page (Site not responding. Last check: 2007-10-09)
		For now, note the name Harry Nyquist, who conceived the idea of digital sampling 60 years before the technology was available to realize his invention.
		Nyquist established the fact that the maximum signaling rate achievable over a circuit is twice the number of...
		In 1928, Harry Nyquist of Bell Telephone Laboratories showed that a sampling rate must be at least twice the maximum frequency that needs to...
	www.amazon.com /phrase/Harry-Nyquist (586 words)

	Analog Devices: Analog to Digital Converters: Tutorial MT-002: What the Nyquist Criterion Means to Your Sampled Data ... (Site not responding. Last check: 2007-10-09)
		Nyquist was working on the transmission of telegraph signals over a channel that was bandwidth limited.
		The mathematical basis of sampling was set forth by Harry Nyquist of Bell Telephone Laboratories in two classic papers published in 1924 and 1928, respectively.
		Note that the image which falls in the first Nyquist zone contains all the information in the original signal, with the exception of its original location (the order of the frequency components within the spectrum is reversed, but this is easily corrected by re-ordering the output of the FFT).
	www.analog.com /en/content/0,2886,760__91249,00.html (3199 words)

	Harry Nyquist: A Founding Father Of Digital Communications (Site not responding. Last check: 2007-10-09)
		Harry Nyquist was born in 1889 in Sweden.
		Nyquist arrived in the U.S. in 1907 and subsequently earned BSEE and MSEE degrees from the University of North Dakota in 1912 and 1915, respectively, and a PhD in physics from Yale University in 1917.
		An outgrowth of Nyquist's work in feedback loops was the "Nyquist plot," which plots the magnitude and phase of a frequency response on orthogonal axes.
	www.elecdesign.com /Articles/ArticleID/11193/11193.html (1128 words)

	Turning Nyquist upside down by undersampling
		In the 1920s, these gentlemen created the now-well-known Nyquist theorem, which states that when sampling a signal at discrete intervals, the sampling must be greater than twice the highest frequency of the input signal.
		In my discussions with engineers, I use the Nyquist theorem to explain the accuracy of sampling systems in which the bandwidth of the signal of interest is less than twice the sampling frequency of the converter.
		This situation is usually an engineer's initial exposure to the Nyquist theorem, in which signals with frequencies greater than one-half of the converter's sampling rate can come back to haunt you.
	www.ferret.com.au /articles/13/0C03A513.asp (685 words)

	ComputerBase - Lexikon: Harry Nyquist
		Harry Nyquist wurde in Nilsby in Schweden geboren und wanderte 1907 in die USA aus.
		Nyquist publizierte seine Forschungsergebnisse 1928 unter dem Titel "Certain topics in Telegraph Transmission Theory", heute bekannt als Nyquist-Shannon-Abtasttheorem.
		Nyquists Abtasttheorem und seine Erforschung der erforderlichen Bandbreite bildeten eine wichtige Grundlage für Claude Shannons theoretische Arbeiten, die letztlich zur Begründung der Informationstheorie führten.
	www.computerbase.de /lexikon/Harry_Nyquist (234 words)

	Control Systems Engineering: Introduction (Site not responding. Last check: 2007-10-09)
		One such person was Harry Black who invented the feedback amplifier to improve telephone carrier capabilities.
		Harry Nyquist and Hendrik Bode built on Blacks work and developed frequency domain techniques.
		Harold Hazen and Vannevar Bush, built network analyzers, circuits for solving equations like the Product Integraph, the Differential Analyzer, and the Cinema Integraph, all tools that were applied during World War II in developing fire control systems for anti-aircraft guns.
	www.rpi.edu /~kracua/seminar/det.html (629 words)

	Nyquist–Shannon sampling theorem - Wikipedia, the free encyclopedia
		This constraint is equivalent to requiring that the system's Nyquist frequency (also known as critical frequency, and equal to half the sample rate) be strictly greater than the bandwidth of the signal.
		The sampling theorem was implied by the work of Harry Nyquist in 1928 ("Certain topics in telegraph transmission theory"), in which he showed that up to 2B independent pulse samples could be sent through a system of bandwidth B; but he did not explicitly consider the problem of sampling and reconstruction of continuous signals.
		The sampling theorem, essentially a dual of Nyquist's result, was proved by Claude E. Shannon in 1949 ("Communication in the presence of noise").
	en.wikipedia.org /wiki/Nyquist-Shannon_sampling_theorem (5181 words)

	Harry Nyquist - Information from Reference.com
		Nyquist moved to the United States in 1907.
		Harry Nyquist (1920's) showed that to distinguish unambiguously between all signal...
		Finally, Harry Nyquist was engaged in studies of feedback amplifiers,...
	dictionary.reference.com /search?q=Harry+Nyquist (235 words)

	Digital Dharma of Audio A/D Converters
		Harry Nyquist discovered while working at Bell Laboratories in the late `20s and wrote a landmark paper [1] describing the criteria for what we know today as sampled data systems.
		For example, the theoretical Nyquist frequency for the audio CD (compact disc) system is 22.05 kHz, equaling one-half of the standardized sampling frequency of 44.1 kHz.
		Nyquist, Harry, "Certain topics in Telegraph Transmission Theory," published in 1928.
	www.rane.com /note137.html (5563 words)

	Definition of Harry Nyquist
		Harry Nyquist (February 7, 1889 - April 4, 1976) was an important contributor to information theory.
		His early theoretical work on determining the bandwidth requirements for transmitting information, as published in "Certain factors affecting telegraph speed" (Bell System Technical Journal, 3, 324-346, 1924), laid the foundations for later advances by Claude Shannon, which led to the development of information theory.
		In 1927 Nyquist determined that an analog signal should be sampled at regular intervals over time and at twice the frequency of its highest-frequency component in order to be converted into an adequate representation of the signal in digital form.
	www.wordiq.com /definition/Harry_Nyquist (258 words)

	SCI0012
		Harry Nyquist at Bell Labs had explored analog-to-digital conversion of modulated analog signals during the 1920’s, but it wasn’t until the invention of the transistor in 1947 (you guessed it, also at Bell Labs) that PCM was commercially feasible.
		The well-known Nyquist sampling principle dictates that any frequency must be sampled at least twice per one cycle in order to be digitized and returned back to its original form using a digital-to-analog converter (DAC).
		Nyquist’s research also showed that frequencies that where not sampled at least twice per cycle appeared as ghost or “alias” signals below half the sampling frequency (designated the “Nyquist frequency”).
	www.lasalle.edu /~weaver/html/sci0012.html (848 words)

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