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Phased-array receivers are popular electronic systems due to the advantages of signal to noise ratio (SNR) improvement and interference cancellation. However, they are mostly discussed on circuit level, and it is hardly seen any systematic design approach for phased-array receivers in general. The scope of this paper is to analyze the difference between phased-array and single-chain receivers from...
Power control is one of the major parts of cellular communication system. The power control helps maintain quality of service of the communication link. In this paper, a simple proportional integral (PI) control is used in the Code Division Multiple Access (CDMA) radio system to maintain the signal to noise ratio (SNR) around a desired level under channel fading environment with multiple access interference...
Because the conditions for video capture is not very good, the SNR of collected video information is usually low. But for users, high-quality video is a basic requirement. How to effectively reduce the noise signal of the video is the key in the video processing system. And we also propose an algorithm for high-quality video from a low SNR video sequence.
In Micro-CT, the smaller voxel requires much higher dose to achieve an adequate signal-to-noise ratio compared to clinical CT. Thus, it necessitates a method that reduces statistical noise in order to improve dose efficiency. We have developed a fuzzy-logic based non-linear Gaussian (NLG) filtering for smoothing projection data before reconstructed. We propose a fuzzy-logic based edge detector to...
The immense scope in the field of biomedical signal processing independent component analysis (ICA ) is gaining momentum due to huge data base requirement for quality testing. The diagnosis of patient is based on visual observation of recorded ECG signals may not be accurate. Many attempts have been carried out to remove noise or artifacts such as interference (few Hz), electromagnetic emission, muscle...
An effective algorithm is proposed to estimate the spread spectrum sequence in direct spread spectrum sequence (DSSS) signal with the non-stationary noise for the underwater acoustic non-cooperative communication system. Conventional estimators are generally ineffective in detecting signals under low signal-to-noise ratio (SNR). The estimator proposed in this paper only needs the demodulation for...
The problem of the detection of a signal in the presence of broad-band noise and interferences that lie in a subspace that is imperfectly known is considered. It is assumed that a basis (or generating set) of the interference subspace is known up to additive white Gaussian noise. This amounts to assuming that each of these basis vectors lies in a cone, the aperture of which depends upon the level...
Reliable spectrum sensing in low signal-to-noise ratio (SNR) condition is one of the major technical challenges in cognitive radio network. In this paper, we propose a robust spectrum sensing algorithm for unsynchronized low SNR OFDM signal by mitigating the impacts of time and frequency offsets with multiple processing time window and sliding frequency correlator, respectively. In addition, considering...
Switching transients generated by a selection diversity combiner corrupt receiver filters and increase the system outage as well as corrupting channel estimation. In order to produce an accurate (transient-free) channel estimate and reduce the internal outage, one prefers small switching rates. Therefore, knowledge of the switching rate provides useful information for system engineers in the design...
In this paper a method for improving the signal-to-noise ratio of individual event-related potentials response is presented. The method is based on adaptive Hermite model filter, where parameters of the Hermite model are adjusted by a variable step size least-mean-square algorithm. The performances of the method are evaluated with both simulations and real measurements of event-related potentials...
High dynamic range (HDR) imaging is used to acquire the full dynamic range of a scene with a camera of limited dynamic range. To this end, an exposure set of the scene is acquired, followed by the linearization of each image with the inverse camera transfer function (CTF), which needs to be measured or estimated. Subsequently, the images are combined into one HDR image. Several weighting functions...
Spectrum sensing is a key enabling technology of cognitive radio. Reliable detection increases access opportunity to temporarily unused bands and prevents harmful interference to the licensed users. Due to the receiver noise, signal attenuation, and multi-path fading effect, however, it is usually not possible to determine the existence of primary signal with absolute certainty. By extracting a global...
In interference limited networks treating interference as noise leads to performance degradation at high transmit powers. This can be avoided with rate splitting schemes (Han-Kobayashi region) where portions of the interference are decoded and removed at each receiver. We propose an algorithmic framework for solving the weighted sum rate maximization problem for the two user case of Gaussian interference...
In this paper, an artificial intelligence technique called Back Propagation Network (BPN) is proposed to cancel the electrocardiogram (ECG) interference in electromyogram (EMG) signal. Conventional filtering techniques are not suitable due to an overlap in spectral content of the EMG and the ECG. The performance evaluation of the proposed technique is done in terms of signal to noise ratio, mean square...
The Paper presents the outlines of the field programmable gate array (FPGA) implementation of real time speech enhancement by spectral subtraction of acoustic noise using dynamic moving average method. It describes an stand alone algorithm for speech enhancement and presents a architecture for the implementation. The traditional spectral subtraction method can only suppress stationary acoustic noise...
We address the problem of generating customized, controlled interference for experimental and testing purposes in wireless sensor networks. The known coexistence problems between electronic devices sharing the same ISM radio band drive the design of new solutions to mitigate interference. The validation of these techniques and the assessment of protocols under external interference require the creation...
As single channel speech enhancement, common methods based on short-time spectral amplitude estimation such as spectral-subtraction and Wiener filtering are considered to be simple and effective for suppressing the additive noise in noisy environments. However, these techniques may distort the high frequency harmonics of speech, which are important to the language understanding. To solve this problem,...
In this paper, the nonlinear approximation by piecewise constants is investigated, and a partition method for balancing the total variation over the intervals is proposed. Based on this method, the result of Kahane is proved, and the application in signal restoration is given. Finally, the numerical experiments are conducted to assess the proposed method in comparison with different wavelet thresholding...
A new adaptive beamforming scheme via noncircularity-rate maximization (NORM) is presented for blind recovery of a narrowband signal with nonzero noncircularity degree (such as AM, ASK and BPSK signals). By maximizing the noncircularity rate of the output signal, this new second-order blind beamformer can directly extract the signal of interest from circular interferences and noise (both are not necessarily...
This paper deals with the problem of probabilistic detection of weak sine waves immersed in noise. The analysis is performed in the frequency domain after a discrete Fourier transform, and it is suited for real-time applications. The detection and false alarm probabilities are provided in analytical form as functions of the sampling parameters and the properties of the time window. In particular,...
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