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Cognitive radio (CR) systems offer higher spectrum utilization by opportunistically allocating the unused spectrum from primary users to secondary users. For CR it is vital to perform fast and accurate spectrum sensing in a wideband and noisy channel. Cyclic feature detection performs well in signal detection and is also highly robust to noise uncertainty. However, it requires a high sampling rate...
This paper presents a novel digital blind calibration method for time interleaved analog to digital converters (TIADCs). A simple cost function based on the cross-correlation of channel statistics is used to derive a steepest descent algorithm for the compensation of timing mismatch errors. Instead of calibrating the timing mismatches independently for each channel, only one adaptation channel needs...
This paper proposes a general structure for FIR filters with adjustable magnitude and phase responses controlled by a few parameters. The Farrow structure which uses one parameter to control the fractional delay of an FIR filter can be viewed as special case. A filter bank structure consisting of different types of linear phase differentiators forms the basis of the structure. The filter bank outputs...
This paper proposes a new perspective on the relationship between the sampling and aliasing. Unlike the uniform sampling case, where the aliases are simply periodic replicas of the original spectrum, random sampling theory shows that the randomization of sampling intervals shapes the aliases into a noise floor in the sampled spectrum. New insights into both the Fourier random sampling problem and...
Improved capacitive touch screen responsiveness can be achieved at the expense of the touch screen controller analog hardware complexity and power consumption. This paper proposes a compressive sensing based approach to exploit the sparsity of simultaneous touches (e.g., 10 or less per person) with respect to the number of sensor nodes (e.g., 100s) to achieve similar levels of responsiveness with...
Loudspeakers in portable consumer electronic devices are frequently small in size. Due to the low sensitivity of their drive units, they are pushed to their power handling and mechanical limits by powerful amplifiers in an attempt to reach high volumes. To protect against excessive diaphragm excursions, a model based algorithm is proposed which regulates the voltage input signal to the loudspeaker...
Capacitive touch screens are ubiquitous in today's electronic devices. Improved touch screen responsiveness and resolution can be achieved at the expense of the touch screen controller analog hardware complexity and power consumption. This paper proposes an alternative compressive sensing based approach to exploit the sparsity of simultaneous touches with respect to the number of sensor nodes to achieve...
This paper proposes a compressive sampling scheme based on random temporal sampling using a successive approximation register (SAR) ADC architecture. Variable wordlength data samples at random sampling times would be produced by the SAR converter, so a modified reconstruction algorithm is proposed to recover signals that are sparse or compressible in a known basis. The modified reconstruction algorithm...
Digital filters with adjustable bandwidth(s) are generally desirable in many applications like audio processing and telecommunication. This paper proposes a generalized Farrow structure for adjustable bandwidth linear-phase FIR filters designed under a minimax design criterion. The bandwidth of the proposed filter structure can be continuously adjusted with an updating routine that only involves a...
Digital filters with adjustable bandwidths controlled by one or two parameters are desirable in many applications. This paper treats the design and implementation of linear phase Finite Impulse Response (FIR) adjustable bandwidth filters using the Farrow structure which employs several basis filters in parallel. The complete development process from basis-filter design optimization to FPGA hardware...
Filterbank implementations and simulations can be used successfully in introductory signal processing lab courses by avoiding some of the analytical complexities and focusing on real-world applications. One excellent area is human hearing where the cochlea is well modelled by a filterbank. A lab project that simulates a cochlear implant (CI) combines elements of signal processing with biomedical engineering...
This paper deals with location estimation in the presence of unreliable measurements (outliers) in large scale geolocation systems. In order to find a way of identifying these outliers, we propose an adaptive RANSAC (Random Sample Consensus) algorithm that maintains a consensus set which iteratively includes inliers and rejects outliers. Numerical experiments are performed to apply the proposed algorithm...
In the electricity market, modeling marginal price facilitates to solve many problems in it. To model the probability density function (PDF) of system marginal price (SMP) in the spot market, positivism analysis on SMP PDF is presented in this paper. In contract to the weakness of some traditional probabilistic distribution model, an alpha-stable distribution model that proposed in this paper, has...
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