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	Differential analyser - Wikipedia, the free encyclopedia
		It is designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration.
		The differential analyser was used in the development of the bouncing bomb, used to attack German hydroelectric dams during World War II.
		Differential analysers have also been used in the calculation of soil erosion by river control authorities.
	en.wikipedia.org /wiki/Differential_analyzer (133 words)

	Technology History -- Bush Differential Analyzer (Site not responding. Last check: 2007-11-06)
		The machine called, “the Bush Differential Analyzer,” was purely mechanical, constructed of wheels and pulleys, filled a room and weighed 100 tons.
		Differential calculations are time consuming and difficult, and being able to perform them with a programmable machine, even if the programming involved adjusting wheel tension, was very valuable.
		On the other hand, the analyzer was prone to failure toward the end of its analysis, losing all of its data up to that point.
	imrl.usu.edu /OSLO/technology_writing/001_005-1.htm (140 words)

	Patent 4293918: Digital differential analyzer with an increment output function
		An analyzer according to claim 1, in which said third operation is effective to modify the value of said second data by a unit increment when said second signal indicates that there exists any increment in said first value with respect to said second value.
		An analyzer according to claim 2, further comprising means coupled between said second and third registers and said second arithmetic logic unit for adjusting the amount of said unit increment relative to the value of said second data.
		As is commonly known, the digital differential analyzer (DDA) is used to solve various linear and nonlinear differential equations at high speed and yet with a relatively high degree of precision and to produce signals representing complicated curves or complicated curved surfaces.
	www.freepatentsonline.com /4293918.html (4551 words)

	World Intellectual Property Organization (Site not responding. Last check: 2007-11-06)
		While the differential indicator is also applicable for feedback on FL of the RL channel state, in data services, link adaptation typically occurs on the forward link, and therefore the exemplary embodiment illustrates a remote station feeding information to the base station about the state of the FL using differential indicators on the RL.
		Differential indicators are transmitted at a higher frequency on a continuous channel.
		The apparatus of claim 13, wherein the plurality of computer-readable instructions are further adapted for: generating differential indicators at a second frequency, the differential indicators indicating changes in the quality of the communication link, wherein the second frequency is greater than the first frequency.
	www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=03/73644.030904&ELEMENT_SET=DECL (8056 words)

	AEI Technologies applied electrochemistry 1-800-793-7751 (Site not responding. Last check: 2007-11-06)
		The Applied Electrochemistry Model S-3A Oxygen Analyzer continuously measures the concentration of oxygen in gases which are clean, dry, and fee of gases which are clean, dry and free of combustibles.
		Zero differential O2 is established by drawing dry reference gas through both the reference and sample ports of the instrument using an external pump, such as the AEI R-2 Flow Controller.
		Pressure between the two gas streams is balanced by adjusting a needle valve is used to induce a measured differential pressure between the gas streams, and the differential O2 concentration this creates is calculated precisely.
	www.aeitecno.com /html/02s3a.html (2585 words)

	UCLA Engineering: History
		Only the sixth instrument of its kind in the United States, the differential analyzer, with its interconnected system of shafts, motors, and gears employs mechanical elements for addition, subtraction, multiplication and division, and electro-mechanical elements for more complex functions.
		Somewhat resembling a telephone switchboard with dials, the analyzer initially was developed by GE to study problems associated with power system design and operation.
		It is the second "mechanical brain" machine to be obtained by the college, the first being the GE differential analyzer, which went into operation a few weeks earlier.
	www.engineer.ucla.edu /history/timeline41_54.html (2322 words)

	Vannevar Bush: The Differential Analyzer, first edition
		Vannevar Bush's Differential Analyzer, the first modern analog computer: totally mechanical in nature, the Differential Analyzer used a complex and ingenious system of rotating shafts and gears to produce solutions to differential equations that had previously been prohibitively difficult.
		The Differential Analyzer, as he called it, was an analog calculator that could be used to solve certain classes of differential equations...
		The differential analyzer became a crucial step in the development of the modern computer.
	www.manhattanrarebooks-science.com /vbush.htm (230 words)

	The Memex (Site not responding. Last check: 2007-11-06)
		From 1928 to 1930, he worked with a team at MIT to develop a prototype for the differential analyzer, one of Bush's most famous and groundbreaking inventions.
		Used before the ENIAC, the differential analyzer was a mechanical calculator that was too complicated and became obsolete with the invention of the electronic computer.
		Eventually, the analog computer finally came into play, which would replace the differential analyzer which was often more of a problem than a solution.
	www.geocities.com /xanqui (876 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		The wheel was driven by friction, and the gear ratio was altered by varying the distance of the wheel from the axis of rotation of the disk.
		Bush's differential analyzer was, however, the first device of sufficiently general application to meet a genuine need, and in the period immediately before and during World War II quite a number of these devices were constructed.
		In 1945, Bush and S. Caldwell described a new differential analyzer in which interconnection between the integrators was effected electrically instead of mechanically.
	engineering.union.edu /~hemmendd/Encyc/Articles/Difanal/difanal.html (939 words)

	Historical Sketch, ENIAC Trial Exhibits Guide
		Though the Bush analyzer was able to perform many mathematical equations, it was still at its core a mechanical device with an electric drive and thus could not produce the greater precision and accuracy desired by scientists.
		The catalyst that advanced electrical engineering and the computer beyond the differential analyzer and to the ENIAC was the demands of the army during the 1930's and particularly the Second World War.
		The practical need that the differential analyzer could not solve effectively was the preparation of firing tables—charts that showed how to aim artillery accurately.
	www.archives.upenn.edu /faids/upd/eniactrial/eniac4.html (1538 words)

	The Differential Analyser Explained
		The mechanical Differential Analyser has intrigued mathematically minded Meccanomen for many years, ever since this machine was first modelled, largely in Meccano, by Douglas Hartree and Arthur Porter at Manchester University in 1934.
		Many full scale non-Meccano Differential Analysers were built in USA, UK and Europe between 1934 and the early 1950s, until they were eventually replaced by faster digital computers.
		Adding units consist of a differential gear system so arranged that the angular rotation of one shaft connected to it is the sum of the angular rotation of two other shafts.
	www.dalefield.com /nzfmm/magazine/Differential_Analyser.html (1785 words)

	UCLA SEAS and the Thinking Machines
		When the machine is in use, the variables in the differential equations being solved are represented by the rotation of shafts in the machine.
		In December of 1977, the last working model of a mechanical differential analyzer in the world is donated by UCLA to the Smithsonian Institution for its pioneering computing display.
		The differential analyzer introduced much of Southern California industry to automatic computing, but became obsolete beginning in 1960 as it was replaced by computing machines with electronic circuits and vacuum tubes.
	www.seas.ucla.edu /hsseas/history/think.html (429 words)

	Physics Department: RG Tropospheric Aerosols-WS Humidity-related properties of atmospheric aerosols (Site not responding. Last check: 2007-11-06)
		In contrast to the DMPS-system (Differential Mobility Particle Sizer) operating at dry conditions, the aerosol flow and the sheath air flow of the DMA can be humidified to relative humidities up to 90% before entering the DMA to measure aerosol particle number size distributions at ambient relative humidity.
		The H-TDMA-system (Hygroscopicity-Tandem Differential Mobility Analyzer) is used to measure the hygroscopic properties of aerosol particles of a certain size as a function of relative humidity.
		A TD-H-TDMA-system (ThermoDenuder-Hygroscopicity-Tandem Differential Mobility Analyzer) is used to determine the hygroscopic properties of the non-volatile mass fraction of the atmospheric aerosol.
	www.tropos.de /eng/PHYSICS/aerosol/humidity/measure.html (844 words)

	Tektronix MBD: Probes Design Information for P6810/6860/6880
		The P6810/6860/6880 Logic Analyzer probes are used with TLA7Axx Logic Analyzer Modules to provide simultaneous analog and digital measurements through a single probe.
		The P6810/6860/6880 logic analyzer probes are the world's first logic analyzer probes to make use of Silicon Germanium (SiGe) technology.
		These new logic analyzer probes capitalize on technology that is being utilized by Tektronix TDS oscilloscopes today.
	www.tek.com /Measurement/logic_analyzers/index/design (347 words)

	differential analyzer -- Encyclopædia Britannica
		The American electrical engineer Vannevar Bush and others at the Massachusetts Institute of Technology invented the first continuous integraph, later called a differential analyzer, during the early 1930s.
		The Differential Analyzer, as he called it, was an analog calculator that could be used to solve certain classes of differential equations, a type of problem common in physics and engineering applications that is often very tedious to...
		The differential applies power as needed to the wheels while they turn at different speeds on curves.
	www.britannica.com /eb/article?tocId=9030411 (738 words)

	Invent Now \| Hall of Fame \| Search \| Inventor Profile
		In 1931, Vannevar Bush completed work on his most significant invention, the differential analyzer, a precursor to the modern computer.
		It used electrical motors to drive shafts and gears that represented terms in complex equations, and was invaluable to scientists and engineers in fields as diverse as ballistics, acoustics, and atomic physics.
		The differential analyzer significantly reduced the time and effort required to carry out such calculations and opened the eyes of many observers to the enormous possibilities of computers.
	www.invent.org /hall_of_fame/203.html (246 words)

	No. 27: Vannevar Bush's Differential Analyzer
		It culminated in 1942 with the dedication of his huge Rockefeller Differential Analyzer at MIT -- a one-hundred-ton machine with 2000 vacuum tubes and 150 motors.
		Owens, L. Vannevar Bush and the Differential Analyzer: The Text and Context of an Early Computer.
		This episode has been revised and expanded as Episode 1319.
	www.uh.edu /engines/epi27.htm (428 words)

	Sable Systems OXZILLA II Differential Oxygen Analyzer
		Clearly the FC2 [Oxzilla] has less signal noise and is more stable (after a couple hours of warmup) than [the competing differential oxygen analyzer], which is an unusually good specimen of that device.
		The OXZILLA II Differential Oxygen Analyzer comes with a three year warranty (Eighteen months on the fuel cells) and lifetime technical support.
		This lets you mount your Oxzilla differential oxygen analyzer in a standard 19" instrument rack, and is ideal if you're constructing a fixed or transportable rack-based gas analysis/respirometry setup.
	www.sablesys.com /oxzilla2.html (1442 words)

	ENIAC, PENNSYLVANIA EVENTS
		The Moore School of Electrical Engineering of the University of Pennsylvania had a Bush differential analyzer that was much larger than the one at Aberdeen, so the Army contracted with the University of Pennsylvania for its use.
		An electronic torque amplifier was also to replace the mechanical ones in the Bush differential analyzer.
		With the Bush differential analyzer, it could be done in about 15 minutes.
	www.geocities.com /Heartland/4547/eniac.html (517 words)

	Bibliography
		Includes a brief mention of the Meccano differential analyzer she built over a 6 week period in the summer of 1948.
		Letters to the editor discussing the differential analyzer, in response to the question from a reader as to whether any significant inventions or principles owe their discovery to the use of Meccano.
		A brief operating manual for the Meccano differential analyzer at MOTAT which indicates that it was in operation in 1978 for demonstrations.
	www.meccano.us /bibliography.html (8424 words)

	No. 1319: Differential Analyzer
		Bush's Analyzer quickly fell under the pall of WW-II secrecy, but only after the head of electrical engineering at MIT had proclaimed it would "mark the beginning of a new era in mechanized calculus," and MIT president Compton had announced it would be "one of the great scientific instruments of modern times."
		Historian Larry Owens looks at this fall from grace and asks sadly, "How does one tell the story of a machine?" Owens concludes that the real importance of the fall is that it so clearly illustrates a change in the character of engineering after the war.
		Owens, L., Vannevar Bush and the Differential Analyzer: The Text and Context of an Early Computer, Technology and Culture, Vol.
	www.uh.edu /engines/epi1319.htm (538 words)

	Electronic Computers Within The Ordnance Corps, Pre-Electronic Computing Devices
		For this reason the design of a second analyzer was begun in 1935, on which all connections could be made electrically.
		The Bush Differential Analyzer, an analog device, was installed under the direction of Major James Guion, who was in charge of the Ballistic Computing Section at Aberdeen Proving Ground at that time.
		During World War II the Bush Differential Analyzer was used primarily to compute trajectories for firing tables and to prepare trajectory charts for use with VT fuzes.
	ftp.arl.mil /~mike/comphist/61ordnance/chap1.html (3063 words)

	Maurice V. Wilkes
		The laboratory was to be called the "Mathematical Laboratory" and was to be equipped with an eight integrator differential analyzer, the model differential analyzer, the "Mallock Machine" - an electrical analog calculating device built in 1933 to solve linear simultaneous equations - and a variety of desk calculators.
		Wilkes' initial brief was to supervise the construction of the new differential analyzer and visit Manchester University to gain experience on the differential analyzer there.
		Wilkes jumped at the chance to go and, although he arrived late owing to post war shipping shortages, he was in time for the detailed description of the ENIAC and the discussion of the EDVAC principle.
	ei.cs.vt.edu /~history/Wilkes.html (2477 words)

	Vannevar Bush's Analog Computer -- The Differential Analyser
		The Differential Analyzer was based on the use of mechanical integrators that could be interconnected in any desired manner.
		In 1935 Bush developed a second version, in which the gears were shifted electro-mechanically and which employed paper tapes to carry instructions and to set up the gears.
		being a major achievement in its own right, the Differential Analyzer was also significant because it focused attention on analog computing techniques, and therefore detracted from the investigation and development of digital solutions for quite some time.
	www.maxmon.com /1927ad.htm (283 words)

	+Mindconnection's Information Connection: Eniac, the first computer
		John Mauchly, who had an idea for an electronic differential analyzer that would solve problems much faster than the mechanical differential analyzer.
		The filaments operated at reduced voltage dc and were never turned off because when the machine was turned on, the heaters of some tubes were certain to fail.
		The ENIAC was able to calculate an artillery trajectory in 30 seconds compared to 15 minutes on the mechanical differential analyzer and twenty man-hours on a desk calculator.
	www.mindconnection.com /library/factfile/eniac.htm (792 words)

	Patent 4563749: Floating point digital differential analyzer
		The present invention relates to a digital differential analyzer (hereinafter referred to as DDA) having addition, subtraction, multiplication and division functions for floating point numbers.
		The DDA is an arithmetic apparatus specifically designed so that variables to be handled among arithmetic operations are converted to increments, thereby simplifing the hardware configuration while precisely and quickly solving a differential equation and/or generating a complex curve or curved surface.
		The conventional FPDDA was developed for primarily solving a differential equation and an integration operation as a primary function thereof.
	www.freepatentsonline.com /4563749.html (5105 words)

	Research Instrumentation (Site not responding. Last check: 2007-11-06)
		The analyzer may be used in flow-through gas exchange systems for real-time respiratory monitoring, or in semi-open and closed systems for measurements at extremely low activity levels.
		The analyzer is a component of our modular gas exchange systems that can be customized to meet all your respirometry requirements.
		All of our analyzers, pumps and flow meters are housed in instrument cases that can be fitted together to form compact gas exchange systems with gas inlets and outlets in the most convenient locations to reduce tubing lengths.
	www.qubitsystems.com /research.html (1148 words)

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