Topic
Spectrum analyzer
About: Spectrum analyzer is a research topic. Over the lifetime, 12217 publications have been published within this topic receiving 101851 citations.
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19 Oct 1997
TL;DR: In this article, an on-line partial discharge (PD) detection technique in power cables is described using a digital spectrum analyzer with a highfrequency preamplifier and several types of high-frequency inductive sensors.
Abstract: This paper describes an on-line partial discharge (PD) detection technique in power cables. The technique uses a digital spectrum analyzer with a high-frequency preamplifier and several types of high-frequency inductive sensors. In extruded and impregnated cables, the PD detection is made in the VHF range. The suitability and the sensitivity of the VHF technique were checked against two other conventional PD detecting methods (Pulse Phase Analyzer and Fast Digital Scope) by performing PD measurements in EPR-insulated cable under laboratory-controlled conditions. The suitability and sensitivity of the VHF method were as good as the two conventional PD detection method. The VHF method runs used to conduct on-site PD measurement in several power cables. These measurements were conducted while the cables were in service. Special care was given to distinguish between external electromagnetic noise and electromagnetic signals produced by the PD activities inside the cable insulation.
58 citations
TL;DR: It is envisioned that a new class of low-power, high-speed, special-purpose signal processors can be realized by spin-waves, and all performance figures of this magnetoelectric device at room temperature may be significantly better than what is achievable in a purely electrical system.
Abstract: We present the design of a spin-wave-based microwave signal processing device. The microwave signal is first converted into spin-wave excitations, which propagate in a patterned magnetic thin-film. An interference pattern is formed in the film and its intensity distribution at appropriate read-out locations gives the spectral decomposition of the signal. We use analytic calculations and micromagnetic simulations to verify and to analyze the operation of the device. The results suggest that all performance figures of this magnetoelectric device at room temperature (speed, area, power consumption) may be significantly better than what is achievable in a purely electrical system. We envision that a new class of low-power, high-speed, special-purpose signal processors can be realized by spin-waves.
58 citations
Patent•
14 Mar 2001
TL;DR: In this article, a method for separating ions is disclosed, where a first analyzer region is defined defined by a space between first and second spaced apart electrodes, and a second analyzer regions is defined in operational communication with the first analyser region and having two electrodes.
Abstract: A method for separating ions is disclosed. A first analyzer region is provided defined by a space between first and second spaced apart electrodes. A second analyser region is defined in operational communication with the first analyzer region and having two electrodes. Ions are provided to one of the first analyzer region and the second analyzer region and then coupled from there to the other analyzer region. A first asymmetric waveform and a first direct-current compensation voltage are applied to electrodes for providing an electric field within the first analyzer region. The first asymmetric waveform is typically selected for effecting a difference in net displacement between two different ions in the time of one cycle of the applied first asymmetric waveform and the first compensation voltage is selected to support selective transmission of a first subset of the ions within the first analyzer region. Conditions are provided within the second analyzer region for effecting a second separation of ions therein to support selective transmission of a second subset of the ions within the second analyzer region.
58 citations
TL;DR: In this paper, the authors report the fabrication and characterization of a high frequency traveling wave electro-optic phase modulator made from thermally cross-linked polyurethane−Disperse Red 19 polymers.
Abstract: We report the fabrication and characterization of a high frequency traveling wave electro‐optic phase modulator made from thermally cross‐linked polyurethane‐Disperse Red 19 polymers. The device has been fabricated using a three layer structure with an integrated 50 Ω microstrip line circuit. The straight channel optical waveguides were defined laterally by standard photolithography and oxygen reactive ion etching. The measured half‐wave voltage was in good agreement with that extrapolated from the second harmonic generation measurements. Optical modulation was observed directly on a spectrum analyzer up to 18 GHz. Long‐term evaluation over an extensive length of time found no observable loss of performance.
58 citations
TL;DR: In this article, a howl detector detects howl contained in the sound signal from a result of frequency analysis by the frequency analyzer, and a controller inputs the calculated coefficients to the digital filter.
Abstract: A sound signal picked-up by a microphone is processed in a howl suppresser including a digital filter. A frequency analyzer performs frequency analysis of the picked-up sound signal. A howl detector detects a howl contained in the sound signal from a result of frequency analysis by the frequency analyzer. A coefficient calculator calculates coefficients to be input to the digital filter to suppress the howl according to a detection result by the howl detector, and a controller inputs the calculated coefficients to the digital filter. The howl detector judges that a maximum peak power level among power levels of the sound signal in a frequency region analyzed by the frequency analyzer is a howl component when a ratio of the maximum peak power level to a mean power level of the sound signal is larger than a predetermined threshold level, preferably for a predetermined threshold time. Also, a threshold controller is provided for controlling the threshold level and/or the threshold time so as to enhance the accuracy of the howl detection.
58 citations