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Broadband receiver design for multi-band multi-standard and software defined radio (SDR) applications has a strong demand for high linearity RF mixers with low power consumption. This paper presents a simple and compact circuit te...
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Broadband receiver design for multi-band multi-standard and software defined radio (SDR) applications has a strong demand for high linearity RF mixers with low power consumption. This paper presents a simple and compact circuit technique for mixer linearization employing a diode linearizer integrated with the mixer's bias circuit. This novel linearization technique effectively compensates the nonlinear distortion and the gain compression of the heterojunction bipolar transistor (HBT), greatly enhancing the mixer linearity at no additional DC power consumption. The proposed mixer is fabricated, together with the conventional design, in a 250 nm SiGe BiCMOS process and tested. Measured results show that with the proposed linearization IIP3 and P-ldB are improved to 18 dBm and -3 dBm from 3 dBm and -9 dBm, respectively.
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摘要 :
Broadband receiver design for multi-band multistandard and software defined radio (SDR) applications has a strong demand for high linearity RF mixers with low power consumption. This paper presents a simple and compact circuit tec...
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Broadband receiver design for multi-band multistandard and software defined radio (SDR) applications has a strong demand for high linearity RF mixers with low power consumption. This paper presents a simple and compact circuit technique for mixer linearization employing a diode linearizer integrated with the mixer's bias circuit. This novel linearization technique effectively compensates the nonlinear distortion and the gain compression of the heterojunction bipolar transistor (HBT), greatly enhancing the mixer linearity at no additional DC power consumption. The proposed mixer is fabricated, together with the conventional design, in a 250 nm SiGe BiCMOS process and tested. Measured results show that with the proposed linearization IIP3 and P-ldB are improved to 18 dBm and -3 dBm from 3 dBm and -9 dBm, respectively.
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Let M = (E, I) be a matroid. A k-truncation of M is a matroid M ' = (E, I' ) such that for any A ? E, A ∈ I' if and only if |A| ≤ k and A ∈ I. Given a linear representation of M we consider the problem of finding a linear repre...
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Let M = (E, I) be a matroid. A k-truncation of M is a matroid M ' = (E, I' ) such that for any A ? E, A ∈ I' if and only if |A| ≤ k and A ∈ I. Given a linear representation of M we consider the problem of finding a linear representation of the k-truncation of this matroid. This problem can be expressed as the following problem on matrices. Let M be a n × m matrix over a field F. A rank k-truncation of the matrix M is a k × m matrix Mk (over F or a related field) such that for every subset I ? {1, . . . , m} of size at most k, the set of columns corresponding to I in M has rank |I| if and only if the corresponding set of columns in M_k has rank |I|. A common way to compute a rank ktruncation of a n×m matrix is to multiply the matrix with a random k×n matrix (with the entries from a field of an exponential size), yielding a simple randomized algorithm. So a natural question is whether it possible to obtain a rank k-truncation of a matrix, deterministically. In this paper we settle this question for matrices over any field in which the field operations can be done efficiently. This includes any finite field and the field of rationals (Q).
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This paper reported a novel high sensitivity and linearity 0-3 kPa piezoresistive pressure sensor by carefully trading off the stress on the beam edge and the deflection of the sensing diaphragm. A shuriken-structured diaphragm (S...
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This paper reported a novel high sensitivity and linearity 0-3 kPa piezoresistive pressure sensor by carefully trading off the stress on the beam edge and the deflection of the sensing diaphragm. A shuriken-structured diaphragm (SSD) was proposed for the first time to improve both sensitivity and linearity for the piezoresistive pressure sensor. The fabricated sensor showed a sensitivity of 4.72 mV/kPa/V and a nonlinearity of 0.18% FSO (full scale output) in the pressure range of 0-3 kPa. Compared with our previous work, the sensitivity was increased by 28.3%, while the nonlinearity was reduced by 50%.
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9-12% Cr martensitic steels are widely used for critical components of new, high-efficiency, ultra-supercritical power plants because of their high creep and oxidation resistances. Due to the time consuming effort of obtaining cre...
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9-12% Cr martensitic steels are widely used for critical components of new, high-efficiency, ultra-supercritical power plants because of their high creep and oxidation resistances. Due to the time consuming effort of obtaining creep properties for new alloys under high temperature creep conditions, in both short-term and long-term testing, it is often dealt with simplified models to assess and predict the future behavior of some materials. In this work, the total time to produce the material fracture is predicted according to models obtained using several linear techniques, since this property is really relevant in power plants elements. These models are obtained based on 344 creep tests performed on modified P92 steels. A multivariate analysis and a feature selection were applied to analyze the influence of each feature in the problem, to reduce the number of features simplifying the model and to improve the accuracy of the model. Later, a training-testing validation methodology was performed to obtain more useful results based on a better generalization to cover every scenario of the problem. Following this method, linear regression algorithms, simple and generalized, with and without enhanced by gradient boosting techniques, were applied to build several linear models, achieving low errors of approximately 6.75%. And finally, among them the most accurate model was selected, in this case the one based on the generalized linear regression technique.
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摘要 :
9-12% Cr martensitic steels are widely used for critical components of new, high-efficiency, ultra-supercritical power plants because of their high creep and oxidation resistances. Due to the time consuming effort of obtaining cre...
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9-12% Cr martensitic steels are widely used for critical components of new, high-efficiency, ultra-supercritical power plants because of their high creep and oxidation resistances. Due to the time consuming effort of obtaining creep properties for new alloys under high temperature creep conditions, in both short-term and long-term testing, it is often dealt with simplified models to assess and predict the future behavior of some materials. In this work, the total time to produce the material fracture is predicted according to models obtained using several linear techniques, since this property is really relevant in power plants elements. These models are obtained based on 344 creep tests performed on modified P92 steels. A multivariate analysis and a feature selection were applied to analyze the influence of each feature in the problem, to reduce the number of features simplifying the model and to improve the accuracy of the model. Later, a training-testing validation methodology was performed to obtain more useful results based on a better generalization to cover every scenario of the problem. Following this method, linear regression algorithms, simple and generalized, with and without enhanced by gradient boosting techniques, were applied to build several linear models, achieving low errors of approximately 6.75%. And finally, among them the most accurate model was selected, in this case the one based on the generalized linear regression technique.
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The main purpose of this paper is to identify a class of SISO systems, which are relatively easy linearizable. These systems are in the so called Linear -Non-Linear (L-NL) form. For systems in the L-NL form it is easy to derive a ...
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The main purpose of this paper is to identify a class of SISO systems, which are relatively easy linearizable. These systems are in the so called Linear -Non-Linear (L-NL) form. For systems in the L-NL form it is easy to derive a linearizing diffeomorphism, which is the identity on a part of the state space, and feedback. Verifiable necessary and sufficient conditions are given in order to check if a system is in the L-NL form, followed by a constructive procedure (which does not require solving a system of first-order partial differential equations) to linearize the system. We illustrate this procedure with a model of turbine.
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This paper describes a method to construct a linear model of a Thyristor-Controlled Series Capacitor (TCSC) by analyzing its response in a time domain simulation wherein the TCSC is represented by a detailed instantaneous value mo...
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This paper describes a method to construct a linear model of a Thyristor-Controlled Series Capacitor (TCSC) by analyzing its response in a time domain simulation wherein the TCSC is represented by a detailed instantaneous value model. To create the linear model Matlab's System Identification ToolBox is used. The linear model in the classic ABCD-form is included in both time simulations and linear analysis of the power system. With this technique, dynamic behaviors of the TCSC are included in linear analysis of the power system. The studied power system is a simplified model of the TCSC compensated south-north link in Brazil. Comparisons between the linear and the instantaneous value model of the TCSC are performed. By using the linear model, simulations can be done much faster (the computing time is reduced) and still include the dominant behavior of the TCSC.
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In this paper we present a Linear prototype Induction Motor (LIM), an iron core armature Permanent Magnet Linear Synchronous Motor (PMLSM), and an ironless armature PMLSM, all of them with the same primary parameters. The electrom...
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In this paper we present a Linear prototype Induction Motor (LIM), an iron core armature Permanent Magnet Linear Synchronous Motor (PMLSM), and an ironless armature PMLSM, all of them with the same primary parameters. The electromagnetic properties of these three prototypes are compared, and the thrust and dynamic performance discussed.
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摘要 :
In this paper we present a Linear prototype Induction Motor (LIM), an iron core armature Permanent Magnet Linear Synchronous Motor (PMLSM), and an ironless armature PMLSM, all of them with the same primary parameters. The electrom...
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In this paper we present a Linear prototype Induction Motor (LIM), an iron core armature Permanent Magnet Linear Synchronous Motor (PMLSM), and an ironless armature PMLSM, all of them with the same primary parameters. The electromagnetic properties of these three prototypes are compared, and the thrust and dynamic performance discussed.
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