This brief presents the concept of adaptive noise cancellation using lms algorithm. The method uses a "primary input" containing the corrupted signal and a "reference input" containing noise correl...
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ISBN:
(纸本)9781479972258
This brief presents the concept of adaptive noise cancellation using lms algorithm. The method uses a "primary input" containing the corrupted signal and a "reference input" containing noise correlated in some unknown way with the primary noise. The reference input is adaptively filtered and subtracted from the primary input to obtain the signal estimate. Extensive Monte Carlo Simulation is carried out and the results are presented using MATLAB.
Although the lms algorithm is often preferred in practice due to its numerous positive implementation properties, once the parameter space to estimate becomes large, the algorithm suffers of slow learning. Many ideas ...
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lms algorithm floating point arithmetic in hardware implementation system takes up more resources,hardware running slow and can not meet the real-time requirements of the *** we need fixed-point arithmetic for lms ***...
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lms algorithm floating point arithmetic in hardware implementation system takes up more resources,hardware running slow and can not meet the real-time requirements of the *** we need fixed-point arithmetic for lms *** algorithm modeling with System Generator in Simulink environment will be implement in ISE and *** can make adjustments and do the corresponding design and simulation for fixed-point *** results show that fixed-point arithmetic module can cellation noise *** compared with floating-point arithmetic modules,there are a little *** algorithm module can achieve lms algorithm *** the Simulink environment,it lay a good foundation for complex system fixed-point implementation.
Solving a high-dimension system identification problem could involve significant challenges in terms of complexity and accuracy of the solution. Due to the large parameter space, a decomposition-based approach fits ve...
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ISBN:
(纸本)9781728189215
Solving a high-dimension system identification problem could involve significant challenges in terms of complexity and accuracy of the solution. Due to the large parameter space, a decomposition-based approach fits very well in this context. This was the idea behind the recently developed iterative Wiener filter for multilinear forms, which reformulates the problem using a combination of shorter filters. Nevertheless, there are inherent limitations related to the Wiener solution, while the least-mean-square (lms) adaptive filter would represent a more practical alternative. Consequently, in this paper, we develop lms-based algorithms for multilinear forms, in the context of a multiple-input/single-output system identification problem. Simulation results indicate the good performance of the proposed algorithms, especially in terms of their fast convergence features.
This paper presents a distributed vibration control method using attachable absorbers for micro-vibration control of large space payload structures. The distributed vibration control system is modeled at three levels....
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This paper presents a distributed vibration control method using attachable absorbers for micro-vibration control of large space payload structures. The distributed vibration control system is modeled at three levels. The simplification of the attachable absorber model is discussed, and the single-channel ANC controller is extended to a multi-channel configuration. Based on the models, simulation analysis is conducted, revealing that the voltage-force output of the absorber in the low-frequency range can be simplified to a second-order system. During the distributed vibration control system simulation, a Simulink-GA hybrid optimization is applied to address the large number of converging parameters. The optimized parameters successfully control the vibration of all channels. Further analysis indicates that the coupling between control channels slightly reduces convergence speed but has no impact on the final control effect. Additionally, the control system can achieve the same results by independently tuning parameters for each channel. The experimental results, using absorber prototypes and a model with 12 sub-mirror structures, demonstrate that the method can control sub-mirror vibrations simultaneously, maintaining the flatness of the main mirror under disturbance, with a 90% reduction in vibration within 4 s. The coupling effect reduces the final convergence speed by approximately 10%, with a time difference of around 1 s.
The control purpose of an electro-hydraulic force control (EHFC) system is to real time replicate the force exerted on a structure in laboratory so as to simulate loads that cannot otherwise be generated naturally. In...
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The control purpose of an electro-hydraulic force control (EHFC) system is to real time replicate the force exerted on a structure in laboratory so as to simulate loads that cannot otherwise be generated naturally. In contrast to electro-hydraulic position control system, the tracking performance of EHFC system is always limited. To enhance the force replication accuracy of EHFC systems, a feedforward inverse controller integrating filtered-x lms adaptive algorithm is presented in this paper. The proposed controller comprises a feedforward inverse controller and an adaptive controller. The feedforward inverse controller working as an inner loop is firstly established by directly cascading the designed parametric inverse transfer function to the EHFC system with proportional integral controller and the inverse transfer function is obtained with the implementation of system identification and zero magnitude error tracking technology. Then, the adaptive controller employing the filtered-x lms algorithm acting as an outer loop is further combined with the feedforward controller to deal with the error occurred in the inverse model design procedure. Therefore, the proposed controller is an easy-to-implement strategy and can effectively enhance the force replication performance for both phase delay errors and amplitude mismatch errors. Finally, a series of experiments are carried out on a real EHFC test rig by means of xPC target technology, and the experimental results indicate that the proposed controller has a relatively better tracking accuracy compared with the proportional integral controller and the feedforward controller. It is also worth noting that the proposed controller can also be extended to other servo control systems where high accuracy tracking performance is required.
Optical imaging spacecraft needs adaptable vibration isolators to convey maneuvering forces stably and attenuate disturbances effectively, especially under multiple-level on-orbit working conditions. This paper propos...
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Optical imaging spacecraft needs adaptable vibration isolators to convey maneuvering forces stably and attenuate disturbances effectively, especially under multiple-level on-orbit working conditions. This paper proposes an active-passive integrated variable stiffness vibration isolator (API-VSVI), which employs a heterogeneous-signal fixed-step least mean square (HS-FSlms) algorithm, to provide the necessary adaptability. Furthermore, the actuator's capacity requirements can be further optimized based on the stiffness adjustment method. The API-VSVI prototype was firstly introduced, and the dynamic model was subsequently developed based on the derived equation of the stiffness. Then, the HS-FSlms algorithm was proposed to simultaneously process the displacement and force signals for two different goals concerning different frequency bands. Through the comparative study of parameters, the appropriate range of the dynamic and control parameters was analyzed, following which one stiffness adjustment method was proposed according to the discussion on multilevel input modes. Finally, it was demonstrated by experiment results that the API-VSVI outperformed the VSVI in shaping the transmitted force. It appears that the maneuvering force amplification is actively regulated at less than 4%, and the disturbance suppression is improved to 92.7% by lowering the stiffness and then actively controlled to 98.5%.
This paper presents analytical equations for optimizing feedforward equalizer (FFE) and decision feedback equalizer (DFE) parameters in a wireline receiver to speed up system-level design and simulations. A minimum me...
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This paper presents analytical equations for optimizing feedforward equalizer (FFE) and decision feedback equalizer (DFE) parameters in a wireline receiver to speed up system-level design and simulations. A minimum mean square error (MMSE)-based approach is applied to the receiver model, and a set of equations is developed to co-optimize FFE and DFE taps. The equations consider the noise sources in wireline links, including the sampling clock jitter. It also considers the effect of the noise correlations on the equalizer parameters. For sampling clock jitter, two separate models are developed to distinguish between sampling for discrete-time and continuous-time FFEs (pre-and post-FFE sampling). Then, the translation of jitter noise to voltage noise is carefully investigated. Jitter noise can be either white or correlated. Later, the developed model is modified to generate different variants of MMSE-based approaches to be used in various practical scenarios a designer may face. This includes the equalizer design for maximum likelihood sequence estimation (MLSE)-based receivers and equalizer design with bounded DFE tap magnitude to control undesired side effects such as error propagation. Finally, the use of "tap skipping" to save FFE hardware resources is investigated. The accuracy of models and the performance of each method is justified through simulations and comparing against the lms adaptation loops.
Adaptive signal processing systems, commonly utilized in applications such as active noise control and acoustic echo cancellation, often encompass nonlinearities due to hardware components such as loudspeakers, microp...
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Adaptive signal processing systems, commonly utilized in applications such as active noise control and acoustic echo cancellation, often encompass nonlinearities due to hardware components such as loudspeakers, microphones, and amplifiers. Examining the impact of these nonlinearities on the overall performance of adaptive systems is critically important. In this study, we employ a statistical-mechanical method to investigate the behaviors of adaptive systems, each containing an unknown system with a nonlinearity in its output. We specifically address two types of nonlinearity: saturation and dead-zone types. We analyze both the dynamic and steady-state behaviors of these systems under the effect of such nonlinearities. Our findings indicate that when the saturation value is equal to the dead-zone width, the mean square errors (MSEs) in steady states are identical for both nonlinearity types. Furthermore, we derive a self-consistent equation to obtain the saturation value and dead-zone width that maximize the steady-state MSE. We theoretically clarify that these values depend on neither the step size nor the variance of background noise.
The Volterra filter is one of the digital filters that can describe nonlinearity. In this paper, we analyze the dynamic behaviors of an adaptive signal processing system with the Volterra filter for nonwhite input sig...
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The Volterra filter is one of the digital filters that can describe nonlinearity. In this paper, we analyze the dynamic behaviors of an adaptive signal processing system with the Volterra filter for nonwhite input signals by a statistical -mechanical method. Assuming the self -averaging property with an infinitely long tapped -delay line, we derive simultaneous differential equations that describe the behaviors of macroscopic variables in a deterministic and closed form. We analytically solve the derived equations to reveal the effect of the nonwhiteness of the input signal on the adaptation process. The results for the second -order Volterra filter show that the nonwhiteness decreases the mean -square error (MSE) in the early stages of the adaptation process and increases the MSE in the later stages.
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