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Frequency response

About: Frequency response is a research topic. Over the lifetime, 25705 publications have been published within this topic receiving 332249 citations.


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TL;DR: In this paper, the application of a composite material as a magneto-electric transducer has been discussed and the results of the measurements on frequency response, transfer characteristics, internal impedance, temperature dependence and noise are discussed.
Abstract: This article deals with the application of a composite material as a magneto-electric transducer. The composite, which has both magneto-strictive and piezo-electric properties was developed at Philips' Research Laboratories. A transducer consisting of a piece of composite appears to be a suitable replacement for e.g. Hall devices, especially in AC applications. It needs only two electrical contacts and has a flat frequency response from a few Hz up to 650 kHz, where mechanical resonance occurs. Several calculations and experiments were carried out on the transducer and its electronic analogon, as well as on the measuring set-up, which had to produce a calibrated magnetic field. The results of the measurements on frequency response, transfer characteristics, internal impedance, temperature dependence and noise are discussed. The construction of a magnetic field probe using the composite is described and finally some other applications are given.

149 citations

Journal ArticleDOI
R.C. Degeneff1
TL;DR: In this article, the authors present a method for calculating terminal and internal impedance versus frequency for a lumped parameter model of a transformer, where the transformer's total frequency response can be accurately determined from this impedance data directly, i.e., the terminal resonance and anti-resonance and internal amplification factor characteristic can be calculated for a single or three-phase transformer model.
Abstract: This paper presents a method for calculating terminal and internal impedance versus frequency for a lumped parameter model of a transformer The transformer's total frequency response can be accurately determined from this impedance data directly, ie, the terminal resonance and anti-resonance and internal amplification factor characteristic can be calculated for a single or three-phase transformer model Since most equipment associated with power system operation can be accurately modeled with lumped parameter networks, this method also provides an accurate, straightforward method for determining the resonance characteristic of those systems An additional significance of this method is that the accuracy of the calculation is limited only by the user's ability to represent the equipment or system Heretofore, the accuracy of this calculation was limited by the simplifying assumptions required of the network model by each solution method This paper presents the definitions and mathematical theory underlying the method Two examples are presented in which comparisons are made between measured and calculated values for a helical air core coil and a 200 MVA single-phase autotransformer The agreement is excellent

149 citations

Journal ArticleDOI
TL;DR: An electro-optic modulator that integrates single-layer graphene in a sub-wavelength thick, reflective modulator structure is reported on, offering solutions to a variety of high-speed amplitude modulation tasks that require optical amplitude modulation without phase distortions, a flat frequency response, or ultra-thin geometries.
Abstract: Graphene’s featureless optical absorption, ultrahigh carrier mobility, and variable optical absorption by an applied gate voltage enable a new breed of optical modulators with broad optical and electrical bandwidths. Here we report on an electro-optic modulator that integrates single-layer graphene in a sub-wavelength thick, reflective modulator structure. These modulators provide a large degree of design freedom, which allows tailoring of their optical properties to specific needs. Current devices feature an active aperture ~100 µm, and provide uniform modulation with flat frequency response from 1 Hz to >100 MHz. These novel, low insertion-loss graphene-based modulators offer solutions to a variety of high-speed amplitude modulation tasks that require optical amplitude modulation without phase distortions, a flat frequency response, or ultra-thin geometries, such as for controlling monolithic, high-repetition rate mode-locked lasers or active interferometers.

149 citations

Journal ArticleDOI
Simone Schuerle1, Sandro Erni1, M. Flink1, Bradley E. Kratochvil1, Bradley J. Nelson1 
TL;DR: In this article, a magnetic manipulation system capable of 5 degree-of-freedom (5DOF) wireless control of micro-and nanostructures (3-DOF position, 2DOF pointing orientation) is presented.
Abstract: We present a magnetic manipulation system capable of 5 degree-of-freedom (5-DOF) wireless control of micro- and nanostructures (3-DOF position, 2-DOF pointing orientation) The system has a spherical workspace with a diameter of approximately 10 mm, and is completely unrestrained in the rotational degrees-of-freedom This is accomplished through the superposition of multiple magnetic fields, and capitalizes on a linear representation of the coupled field contributions of multiple soft-magnetic-core electromagnets acting in concert The system consists of 8 stationary electromagnets with ferromagnetic cores, and is capable of producing arbitrary magnetic fields and field gradients up to 50 mT and 5 T/m at frequencies up to 2 kHz The capabilities of the system are evaluated through the introduction of the reachable magnetic workspace of the system as well as frequency response and calibration results Experimental results are presented which demonstrate different magnetic control strategies at sub-mm and sub-μm scale

149 citations

Journal ArticleDOI
TL;DR: Recommendations on desirable microphone characteristics, while preliminary and in need of further numerical justification, should provide the basis for better accuracy and repeatability of studies on voice and speech production in the future.
Abstract: Purpose This tutorial addresses fundamental characteristics of microphones (frequency response, frequency range, dynamic range, and directionality), which are important for accurate measurements of voice and speech. Method Technical and voice literature was reviewed and analyzed. The following recommendations on desirable microphone characteristics were formulated: The frequency response of microphones should be flat (i.e., variation of less than 2 dB) within the frequency range between the lowest expected fundamental frequency of voice and the highest spectral component of interest. The equivalent noise level of the microphones is recommended to be at least 15 dB lower than the sound level of the softest phonations. The upper limit of the dynamic range of the microphone should be above the sound level of the loudest phonations. Directional microphones should be placed at the distance that corresponds to their maximally flat frequency response, to avoid the proximity effect; otherwise, they will be unsuit...

148 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023154
2022389
2021857
20201,105
20191,212
20181,152