Topic
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 authors proposed a multi-objective optimization algorithm to find the suitable value of inertia constant for low inertia microgrids such that the frequency stability is preserved with a lower cost.
127 citations
Patent•
23 Jun 2011
TL;DR: In this paper, an electronic device is disclosed comprising an acceleration sensor operable to generate an acceleration signal, and a free fall detector operating in response to the acceleration signal is disabled when a magnitude of the frequency response within one of a plurality of frequency bands exceeds a threshold, wherein each frequency band corresponds to one of the normal operating modes.
Abstract: An electronic device is disclosed comprising an acceleration sensor operable to generate an acceleration signal, and a free fall detector operable to detect a free fall event in response to the acceleration signal. A frequency response of the acceleration signal is measured, and the free fall detector is disabled when a magnitude of the frequency response within one of a plurality of frequency bands exceeds a threshold, wherein each frequency band corresponds to one of a plurality of normal operating modes.
127 citations
TL;DR: In this article, the design of quadrature mirror filter (QMF) banks whose analysis and synthesis filters have linear phase is considered and an analytical solution formula is obtained, leading to a very efficient procedure.
Abstract: The design of quadrature mirror filter (QMF) banks whose analysis and synthesis filters have linear phase is considered. Because the design problem in the frequency domain is a highly nonlinear optimization problem, a linearization technique is proposed. An analytical solution formula is obtained, leading to a very efficient procedure. Computer simulations show that the design technique achieves better results in fewer iterations than conventional approaches when starting at the same preset initial guess. Moreover, the technique produces almost the same good results in six iterations if it starts at a better initial guess compared to the preset initial guess. By incorporating the technique with a weighted least squares, (WLS) algorithm, the design of QMF banks whose overall reconstruction error is minimized in the minimax sense over the entire frequency band is facilitated. Computer simulations for illustration and comparison are provided. >
127 citations
TL;DR: In this article, a photonic assisted broadband and high-resolution radio-frequency (RF) channelization scheme based on dual coherent optical frequency combs (OFCs), regular optical de-muxes, and I/Q demodulators is analyzed and experimentally demonstrated.
Abstract: In this paper, a novel photonic-assisted broadband and high-resolution radio-frequency (RF) channelization scheme based on dual coherent optical frequency combs (OFCs), regular optical de-muxes, and I/Q demodulators is analyzed and experimentally demonstrated. The use of two coherent combs avoids precise optical alignment, and a numerical filter in digital signal processor (DSP) enables an ideal rectangular frequency response in each channel without any ultranarrow optical filters. Besides, due to the use of I/Q demodulators, ambiguous frequency estimate in direct detection is avoided. By using two coherent OFCs with the free spectrum range (FSR) of about 40 GHz, we experimentally demonstrate the channelization scheme with seven channels, 500-MHz channel spacing, and frequency coverage from 3.75 to 7.25 GHz. The input RF tones are accurately downconverted to an intermediate frequency (IF) with a maximum frequency error of 125 kHz. Meanwhile, the channel frequency response and crosstalk of the scheme are also evaluated experimentally.
126 citations
TL;DR: In this paper, a new method for estimating parameters of non-linear parametric models that uses internal feedback to account for nonlinearities is presented, and the method estimates the linear frequency response matrix and nonlinear system parameters at forced and unforced degrees of freedom of general multiple-degree-of-freedom nonlinear systems simultaneously.
126 citations