A direct digital frequency synthesizer with single-stage delta-sigma interpolator and current-steering DAC

This paper presents a direct digital frequency synthesizer (DDFS) with a 16-bit accumulator, a 4th-order single-stage pipelined delta-sigma interpolator and a 300MS/s 12-bit current-steering DAC based on Q(2) Random Walk switching scheme. The delta-sigma interpolator is used to reduce the phase truncation error and the ROM size. The measured spurious-free dynamic range (SFDR) is greater than 80 dB for 8-bit phase value and 12-bit sine-amplitude output. The DDFS prototype is fabricated in a 0.35um CMOS technology with core area of 1.11mm(2).

A direct digital frequency synthesizer with fourth-order phase domain Delta Sigma noise shaper and 12-bit current-steering DAC

This paper presents a direct digital frequency synthesizer (DDFS) with a 16-bit accumulator, a fourth-order phase domain single-stage Delta Sigma interpolator, and a 300-MS/s 12-bit current-steering DAC based on the Q(2) Random Walk switching scheme. The Delta Sigma interpolator is used to reduce the phase truncation error and the ROM size. The implemented fourth-order single-stage Delta Sigma noise shaper reduces the effective phase bits by four and reduces the ROM size by 16 times. The DDFS prototype is fabricated in a 0.35-mu m CMOS technology with active area of 1.11 mm(2) including a 12-bit DAC. The measured DDFS spurious-free dynamic range (SFDR) is greater than 78 dB using a reduced ROM with 8-bit phase, 12-bit amplitude resolution and a size of 0.09 mm(2). The total power consumption of the DDFS is 200)mW with a 3.3-V power supply.

Drift distance survey in direct plasma injection scheme for high current beam production

In a laser ion source, plasma drift distance is one of the most important design parameters. Ion current density and beam pulse width are defined by plasma drift distance between a laser target and beam extraction position. In direct plasma injection scheme, which uses a laser ion source and a radio frequency quadrupole linac, we can apply relatively higher electric field at beam extraction due to the unique shape of a positively biased electrode. However, when we aim at very high current acceleration such as several tens of milliamperes, we observed mismatched beam extraction conditions. We tested three different ion current at ion extraction region by changing plasma drift distance to study better extraction condition. In this experiment, C6+ beam was accelerated. We confirmed that matching condition can be improved by controlling plasma drift distance.

Direct and inverse transient eddy current problems

Die vorliegende Arbeit behandelt Vorwärts- sowie Rückwärtstheorie transienter Wirbelstromprobleme. Transiente Anregungsströme induzieren elektromagnetische Felder, welche sogenannte Wirbelströme in leitfähigen Objekten erzeugen. Im Falle von sich langsam ändernden Feldern kann diese Wechselwirkung durch die Wirbelstromgleichung, einer Approximation an die Maxwell-Gleichungen, beschrieben werden. Diese ist eine lineare partielle Differentialgleichung mit nicht-glatten Koeffizientenfunktionen von gemischt parabolisch-elliptischem Typ. Das Vorwärtsproblem besteht darin, zu gegebener Anregung sowie den umgebungsbeschreibenden Koeffizientenfunktionen das elektrische Feld als distributionelle Lösung der Gleichung zu bestimmen. Umgekehrt können die Felder mit Messspulen gemessen werden. Das Ziel des Rückwärtsproblems ist es, aus diesen Messungen Informationen über leitfähige Objekte, also über die Koeffizientenfunktion, die diese beschreibt, zu gewinnen. In dieser Arbeit wird eine variationelle Lösungstheorie vorgestellt und die Wohlgestelltheit der Gleichung diskutiert. Darauf aufbauend wird das Verhalten der Lösung für verschwindende Leitfähigkeit studiert und die Linearisierbarkeit der Gleichung ohne leitfähiges Objekt in Richtung des Auftauchens eines leitfähigen Objektes gezeigt. Zur Regularisierung der Gleichung werden Modifikationen vorgeschlagen, welche ein voll parabolisches bzw. elliptisches Problem liefern. Diese werden verifiziert, indem die Konvergenz der Lösungen gezeigt wird. Zuletzt wird gezeigt, dass unter der Annahme von sonst homogenen Umgebungsparametern leitfähige Objekte eindeutig durch die Messungen lokalisiert werden können. Hierzu werden die Linear Sampling Methode sowie die Faktorisierungsmethode angewendet.

Theoretical and practical electrical engineering; comprising a course of lectures given at the Bliss Electrical School upon the principles and applications of both direct and alternating current apparatus

Mode of access: Internet.

Foreign direct investment in the United States : an update : review and analysis of current developments : a report submitted to the Committee on Energy and Commerce, the Committee on Ways and Means, and the Committee on Foreign Affairs of the House of Representatives, to the Committee on Finance, the Committee on Commerce, Science and Transportation, and the Committee on Foreign Relations of the Senate, and to the Joint Economic Committee of the Congress in response to section 3(a) of the Foreign Direct Investment and International Financial Data Improvements Act of 1990.

"January 1995."

Intermediate (direct and general support) maintenance manual : generator set, gas turbine engine driven, skid mounted, 150 kw, alternating current, tactical model D424A (6115-01-113-1093).

"18 October 1982."

Direct support, general support, and depot maintenance repair parts and special tools lists : welding machine, arc, AC/DC, 300 amp, transformer rectifier, constant current, base mounted (Eutectic Corp. model MD301 FED), FSN 3431-235-4728.

"October 1971."

Laboratory manual, direct and alternating current,

Mode of access: Internet.

Direct support and general support maintenance repair parts and special tools lists (including depot maintenance repair parts and special tools) : generator, engine accessory (alternating current): Prestolite model AMA-5102UT (FSN 2920-909-2483): Leece-Neville models 3002AC and 3002AD (FSN 2920-909-2483), 5504AA and 5504AB (FSN 2920-475-1446), 2184AC (FSN 2920-782-1955), 5300GP (FSN 2920-818-8635).

Includes index.

Operator, organizational, direct support and general support maintenance manual : welding machine, ARC, AC/DC, 300 AMP, transformer rectifier, constant current, base mounted (Eutectic Corp. model MD301 FED) FSN 3431-235-4728.

Includes index.

Organizational, direct and general support, and depot maintenance repair parts and special tools list : welding machine, ARC, G.E.D. generator, 300 amp, DC, constant current, consistant potential, skid mounted, (Libby welding model LTO 300), FSN 3431-253-0558.

"March 1971."

Operator, organizational, direct support, and general support maintenance manual : welding machine, arc, AC/DC, 300 amp, transformer rectifier, constant current, base mounted (Eutectic Corp. model MD301 FED), FSN 3431-235-4728.

"September 1970."

Organizational, direct support, and general support maintenance repair parts and special tools list (including depot maintenance repair parts and special tools) for generator set, gas turbine engine driven, skid mounted, 150 KW, alternating current, tactical, model D 424A NSN 6115-01-113-1093.

Includes index.

California digest supplement, 1915-1919; a digest of the cases decided by the Supreme and Appellate courts of California and by the federal courts on questions of California law since Kerr's California digest, as contained in Raymond's 1916 supplement and in the 1917-1919 California current digests, inclusive, up to volume 178 California Supreme court reports, volume 37 California Appellate reports, and up to 58 California decisions, page 137; California Appellate decisions, page 258; 182 Pacific reporter (California cases), page 991; 258 Federal reporter (California cases), page 161; 39 Supreme court reporter (California cases), page 568. With references to Ruling case law, and important notes in American decisions, American state reports, Annotated cases, Lawyers' reports annotated, and American law reports, also an alphabetical table, direct and reverse, of all cases digested, showing on what page and under what subject each case is found digested in this digest, and also where the various California cases are cited in annotations in "The American series of annotated reports".

Mode of access: Internet.