Second-order intermodulation products are produced by non-linearities in the transfer functions of the receiver's signal processing blocks. Especially in homodyne receivers the second-order intermodulations are pr...
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ISBN:
(纸本)9781424476855
Second-order intermodulation products are produced by non-linearities in the transfer functions of the receiver's signal processing blocks. Especially in homodyne receivers the second-order intermodulations are problematic since they are convolved into baseband and overlap the wanted signal. In this paper a least-mean-square (LMS) adaptive filter approach to estimate and cancel the transmitter (TX) induced second-order intermodulation distortion (IMD2) in the digital domain is presented. The performance of the proposed cancellation method and its dependency on the number of used filter coefficients is verified on measured data of the digital front end (DFE) output of an UMTS transceiver chip.
In the distribution system, voltage sags and swell have adverse effects on sensitive and critical loads. Dynamic Voltage Restorer (DVR) play a vital role to mitigate voltage sags and swell through its organized contro...
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In the distribution system, voltage sags and swell have adverse effects on sensitive and critical loads. Dynamic Voltage Restorer (DVR) play a vital role to mitigate voltage sags and swell through its organized control when connected in series with the system. Various conventional control schemes have been reported for the control of DVR. The performance of DVR with these schemes has been successful in the mitigation of voltage sags/swell, but drawbacks, such as undershoot, and overshoot during sag dynamics are observed in the regulated load terminal voltage. These drawbacks may cause malfunctioning of the equipment connected and hence their elimination is indispensable. With this inspiration, a novel Adaline filter-based adaptive control scheme using learning-rate parameter-based least-mean-square algorithm has been proposed. This scheme has the capability to overcome the drawbacks with the conventional control schemes thus improving the performance of DVR. In this paper, the performance of DVR using proposed algorithm is compared with that using synchronous reference frame (SRF)-based conventional control scheme. The performance is studied and validated through simulation results under different voltage sag and swell conditions in MATLAB software using Sim Power System toolboxes.
Many practical applications built around adaptive algorithms require solutions that work at low signal-to-noise ratio (SNR) values. In this situation, a variable step-size algorithm is a must to accommodate this scena...
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Many practical applications built around adaptive algorithms require solutions that work at low signal-to-noise ratio (SNR) values. In this situation, a variable step-size algorithm is a must to accommodate this scenario. A plethora of variable step algorithms exist in the literature for high SNR values. This paper presents a different variable step-size incremental leastmeansquare strategy that provides excellent performance at low SNR values. A detailed theoretical analysis has been carried out for the proposed algorithm. Simulations have been performed for different scenarios to demonstrate the validity of the proposed strategy. (C) 2020 Elsevier B.V. All rights reserved.
A new variable step-size strategy for the leastmeansquare (LMS) algorithm is presented for distributed estimation in adaptive networks using the diffusion scheme. This approach utilizes the ratio of filtered and win...
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A new variable step-size strategy for the leastmeansquare (LMS) algorithm is presented for distributed estimation in adaptive networks using the diffusion scheme. This approach utilizes the ratio of filtered and windowed versions of the squared instantaneous error for iteratively updating the step-size. The result is that the dependence of the update on the power of the error is reduced. The performance of the algorithm improves even though it is at the cost of added computational complexity. However, the increase in computational complexity can be minimized by careful manipulation of the update equation, resulting in an excellent performance-complexity trade-off. Complete theoretical analysis is presented for the proposed algorithm including stability, transient and steady-state analyses. Extensive experimental analysis is then done to show the performance of the proposed algorithm under various scenarios.
This paper discusses the theory and implementation of an adaptive controller which can track plant with time-varying parameters as well as time-varying transport delay. It also allows for closed-loop pole placement an...
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This paper discusses the theory and implementation of an adaptive controller which can track plant with time-varying parameters as well as time-varying transport delay. It also allows for closed-loop pole placement and, because there are no restrictions on closed-loop zeros, good set-point tracking can be achieved. The scheme is based on the well-known least-mean-square algorithm to generate a finite impulse response (F.I.R.) controller and can therefore be implemented readily using one of the new generation signal processor chips.
This paper focuses on an application of an electro-hydraulic force tracking controller combined with an offline designed feedback controller (ODFC) and an online adaptive compensator in order to improve force tracking...
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This paper focuses on an application of an electro-hydraulic force tracking controller combined with an offline designed feedback controller (ODFC) and an online adaptive compensator in order to improve force tracking performance of an electro-hydraulic force servo system (EHFS). A proportional-integral controller has been employed and a parameter-based force closed-loop transfer function of the EHFS is identified by a continuous system identification algorithm. By taking the identified system model as a nominal plant model, an H offline design method is employed to establish an optimized feedback controller with consideration of the performance, control efforts, and robustness of the EHFS. In order to overcome the disadvantage of the offline designed controller and cope with the varying dynamics of the EHFS, an online adaptive compensator with a normalized least-mean-square algorithm is cascaded to the force closed-loop system of the EHFS compensated by the ODFC. Some comparative experiments are carried out on a real-time EHFS using an xPC rapid prototype technology, and the proposed controller yields a better force tracking performance improvement.
Technologically assistive devices are increasingly playing more important roles in the lives of persons with disabilities, with one of the more promising considerations being a combination of the functions of computer...
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Technologically assistive devices are increasingly playing more important roles in the lives of persons with disabilities, with one of the more promising considerations being a combination of the functions of computer software and hardware. However, using a conventional keyboard for Internet access is prohibitive for persons whose hand coordination and dexterity are impaired by ailments such as amyotrophic lateral sclerosis, multiple sclerosis, muscular dystrophy, and other severe handicaps. To assist participants with physical disabilities in sharing the resources of the Internet, we designed and implemented an easy-to-operate wireless input interface using Morse code as the adaptive communication tool. Moreover, a adaptive Morse code recognition process is introduced. After two months' practice on this system, three participants with physical disabilities could conveniently gain access to the Internet.
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