Results 261 to 270 of about 776,968 (306)

Optical Coherent Transients by Laser Frequency Switching

Physical Review Letters, 1976
A simple method for observing coherent optical-transient phenomena is described. Effects such as photon echoes and free induction decay (FID) should allow studies of the dynamic properties of atoms, molecules, and solids on a time scale ranging from milliseconds to \ensuremath{\sim} 50 ps. The frequency of a cw dye laser is switched with an intracavity
Azriel Z. Genack, Richard G. Brewer
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Frequency-Sensitive Switching Circuit

Review of Scientific Instruments, 1956
A frequency-sensitive switching circuit is described which automatically selects between two ranges of an otherwise conventional frequency meter by switching the leak resistor of the integrating circuit. The basis of the unit is a diode pump integrator operated as a nonlinear device to obtain maximum sensitivity.
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High switching frequency power converters

Proceedings 1995 Canadian Conference on Electrical and Computer Engineering, 2002
The problems of PWM power converters operating at high switching frequency are analyzed and recent techniques of resonant power converters are reviewed. Their limitations are also discussed. New resonant power converters are proposed that can keep the switching frequency constant and at the same time maintain the desirable zero current or zero voltage ...
null Yan-Fei Liu, P.C. Sen
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Frequency modulated switching regulator

1979 IEEE Power Electronics Specialists Conference, 1979
A novel switching regulator power supply is de­scribed which uses frequency modulation to accom­plish duty factor control. The circuit resembles a choke-fed dc-dc converter. A distinguishing feature is that the output transformer is designed purposely to saturate.
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Frequency switching speed measurement of frequency synthesizers

IEEE Transactions on Instrumentation and Measurement, 1986
Application of the spread spectrum technique in communication, radar, and automatic test equipment (ATE) systems requires fast and accurate frequency switching, hopping, or stepping capabilities by the signal sources. This requirement has introduced a new market for high-speed frequency switching synthesizers.
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High Frequency Switching

2011
The meaning of the term high frequency switching as related to a synchronous buck converter applications depends on the power range, the step in the voltage conversion and the switching performance of MOSFETs used as power switches. In a power range of 1 W, and low input voltages, a switching frequency up to 10 MHz can be reasonably achieved.
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Frequency content of switching overvoltages

Proceedings of the Institution of Electrical Engineers, 1976
Switching overvoltages are usually discussed in terms of their peak values, but their frequency content is also important. The relevant frequencies have now been analysed for certain field-test waveforms as well as for calculated voltage transients that result from energising a single line.
D.F. Binns, H. Habibollahi
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Improving Frequency Measurements: Switching Loads

IEEE Transactions on Power Delivery, 2006
Frequency recording units (FRUs), designed to measure power systems' frequency at low voltage, are affected by the connection of large loads causing sudden phase shifts and magnitude changes in the voltage. These phase shifts introduce spikes in the frequency measured by FRUs.
M.A. Donolo, V.A. Centeno, Y. Liu
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High-frequency phenotypic switching in Candida albicans

Trends in Genetics, 1993
Most strains of Candida albicans are capable of switching spontaneously and at high frequencies between a number of phenotypes distinguished by colony morphology. Unlike switching in many other microbial pathogens, switching in C. albicans is pleiotropic, affecting several morphological and physiological parameters.
D R, Soll, B, Morrow, T, Srikantha
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Interleaved or sequential switching - for increasing the switching frequency

2007 7th Internatonal Conference on Power Electronics, 2007
Using several IGBTs in parallel it is possible to operate standard IGBTs with higher switching frequencies than usual. Based on this concept the current load and thermal losses are split between the paralleled devices. The free wheeling diodes, however, cannot be controlled actively and therefore do not share in sequential switching.
Andre Cabral Ferreira, Ralph M. Kennel
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