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An important application of Active Noise Control (ANC) is to reduce noise produced by machinery in modern living places. We present an ANC system that is designed to cancel narrowband noise generated from the compressor of an HVAC (Heating, Ventilation, and Air-Conditioning) system in real time. To achieve cost effectiveness of the system, we propose a singlechannel Feedback ANC implementation, which...
We present a class of mixed adaptive filters that are able to switch between several modes of operation according to the statistical characteristics of the unknown noise when the class of true signals is known. The operation of the filters is explained in connection to the noise type.
In many applications, image and video signals are corrupted by impulse noise during acquisition or transmission. Hence there is a need for an efficient and consumer friendly impulse noise removal technique. In this paper, an efficient low cost VLSI architecture for the edge preserving impulse noise removal technique has been proposed. The architecture comprises of two line buffers, register banks,...
In a teleconference system, the acoustic coupling between loudspeakers and microphones causes that, after talking, the user receives back his own voice. The use of adaptive filters based on the Wiener theory has been established during the last decades in acoustic echo cancellation. This paper proposes a new approach based on cepstral analysis to identify and cancel the echo path. The results show...
In a public address system, due to the amplification system, the source and loudspeaker signals are correlated. Acoustic feedback cancellation methods based on the Wiener theory present a bias in the estimate of the feedback path if no decorrelation algorithm is used. This work presents a new approach based on cepstral analysis to identify and cancel the feedback path. The only known previous cepstrum...
This paper first revisits least mean modulus (LMM) algorithm for complex-domain adaptive filters, presents a mathematical model for impulsive observation noise called CGN, and reviews recursive least moduli (RLM) algorithm that combines the LMM algorithm with recursive estimation of inverse covariance matrix of filter inputs. The RLM algorithm is effective in making the convergence of an adaptive...
In this paper, we propose a microphone array method for an acoustic OFDM (Orthogonal Frequency Division Multiplexing) system. Recently, acoustic OFDM, which uses audible sound waves as an information transmission medium, has been studied. In acoustic OFDM, the transmission characteristic deteriorates owing to acoustic ambient noise because the acoustic noise corrupts audio signals containing embedded...
This paper is to propose an efficient novel method for the wire fault detection with transfer function analysis using time domain reflectometry (TDR), iterative deconvolution and optimization techniques. The paper shows how iterative deconvolution and optimization techniques are used to locate hard faults, enhance the signal-to-noise ratio for detecting small discontinuities. This developed method...
In order for modern factories to meet the future intelligent requirements, wearable supporting technology is introduced to assist the technicians. Technicians could operate interaction electronic technical manual (IETM) and get remote technical support from the wireless local network. To allow the technicians work unencumbered by the device, Head mount display (HMD) and Voice user interface (VUI)...
In this paper, the Allan variance technique is used in analyzing the output signal of a fiber optic gyroscope, by which the characteristics of the noise terms in the angular velocity data was determined. Then we process the random drift data of the FOG with a Kalman Filter based on the theory of time series analysis. On the other hand, an LMS adaptive filter is also applied to the random drift data...
Fault Tolerant Adaptive Filters (FTAFs) rely on inherent learning capabilities of the adaptive process to compensate for transient (soft) or permanent (hard) errors in hardware implementations. This paper investigates fault tolerant transform domain adaptive noise canceling filters to cancel noise from corrupted speech signals. Two transform domain adaptive FIR architectures are compared, one based...
In this paper, we investigate the aspects of constructing an electronic stethoscope with the capability to filter out heart sound from the lung sound pickups in real time. Such a capability is most useful for the clinical diagnosis of pulmonary diseases. The proposed filter design is based on the adaptive line enhancer (ALE) filter structure to be implemented in an FPGA based platform. The DE2-70...
For SINS/GPS integrated navigation system with unknown measurement noise covariance matrix, adopting the conventional Kalman filtering approach to estimate the navigation system errors will lead to a large state estimation error or even make the filter diverge. To solve this problem, an adaptive sequential Kalman filter is presented, in which the measurement noise covariance matrix is estimated on-line...
A high performance Phase-Locked Loop (PLL) based on cascade adaptive notch filters (ANF) is proposed for polluted utility grid in this paper. The proposed cascade structure can regenerate a new signal similar to the fundamental component of the original grid voltage sample signal with the same amplitude and no phase shift. Compared to traditional PLL, The proposed PLL is more accurate especially when...
It is stated that the process of digital signal processing, often to deal with some unforeseen signal, noise or time-varying random signals. In this paper it is shown that only by a two FIR and IIR filter of fixed coefficient optimal filtering cant be achieved. Under such circumstances, it is necessary to design adaptive filters, to track the changes of signal and noise. In present work Adaptive Filter...
The mean filter can remove the Gaussian noise of an image, and the median filter can remove salt and pepper noise of an image. But two methods both result in some loss of image detail and edge information. In fact, image noise is often mixed, and filters above are not good at removing mixed noise. In this paper an improved adaptive image filter is proposed. According to compare the value of seed pixel...
Filtered-x algorithm has a possibility of making an active noise control (ANC) unstable due to the modeling error of a secondary path. A pre-inverse type ANC is proposed in order to solve the problem. The proposed ANC uses the filter which has the inverse transfer function of a secondary path before the secondary path. Whereas the filtered-x algorithm controls a primary path and a secondary path simultaneously...
Vehicular Ad-hoc Networks (VANETs) are distributed, self-organizing communication networks built up by moving vehicles, and are thus characterized by a very high node mobility and limited degrees of freedom in the mobility patterns. Such particular features often make standard networking protocols inefficient or unusable in VANETs. In the past, the wireless networking community relied on simple models...
In this research, the new system which can eliminate the power line interference (PLI) from the electrocardiogram (ECG) signal is proposed. The system consists of a band pass filter, an automatic gain control and an adaptive filter. With the proposed system, the varied frequency and varied amplitude of the power line interference can be significantly eliminated from the ECG signal. In addition, the...
Ease of adaptive filter techniques of its implementation introduce various active noise control (ANC) systems, using different algorithms for efficient and effective acoustic noise control. Filtered-x least mean square (FxLMS) ANC system is used due to secondary path timing delay. In this paper comparison between feed-forward and feedback active noise control system using FxLMS algorithm is done for...
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