The Experts below are selected from a list of 195852 Experts worldwide ranked by ideXlab platform
S K Mitra - One of the best experts on this subject based on the ideXlab platform.
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EFFICIENT MULTISTAGE COMB-MODIFIED ROTATED SINC (RS) DECIMATOR
2014Co-Authors: Gordana Jovanovic-dolecek, S K MitraAbstract:This paper presents a new multistage comb-rotated sinc (RS) decimator. The proposed structure consists of different cascaded comb sections, each down-sampled by a specific down-sampling factor. The number of sections depends on the decimation factor of the original comb decimator. The first section is realized in a non-recursive form. Using the polyphase decomposition, the sub-filters of the first section can be operated at lower rate which depends on the down-sampling factor of the first section. Additionally, the rotated sinc (RS) filter is cascaded in the second section, thus permitting both multipliers of the RS filter to work at the lower rate. The Magnitude Response of the proposed structure is better than that of the original comb decimator. Figure 1: CIC decimation filter The above decimation filter is attractive in many applications because of its very low complexity. It should be noted that while the differentiator section operates at the lower data rate, the integrator section works at the higher input data rate resulting in a larger chip area and a higher power consumption especially when the decimation factor and the filter order are high [3]. The use of a non-recursive equivalent to Eq. (1) reduces power consumption and increases the circuit speed [3-5]. More details on a comparison of the performances of the recursive and non-recursive implementation are given in [3]. In this paper we propose a new multistage structure in which the first stage is implemented non-recursively while all other stages are implemented recursively. The Magnitude Response of this structure is improved over that of the original comb filter by using a modified rotated sinc (RS) filter introduced in [6]. Unlike the structure advanced in [6], where one multiplier works at the high input rate, in the structure proposed in this paper, both multipliers work at the lower rate
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A NEW SHARPENED CASCADED COMB-COSINE DECIMATION FILTER
2008Co-Authors: Gordana Jovanovic Dolecek, S K MitraAbstract:This paper presents a new multistage comb-cosine decimation filter with the improved Magnitude Response. The proposed structure consists of a comb section followed by different cascaded comb and cosine prefilter sections, each down-sampled by a specific down-sampling factor. The number of sections depends on the decimation factor of the original comb decimator, and the number of cascaded filters can be different for different stages. The first section is realized in a non-recursive form. Using the polyphase decomposition, the subfilters of the first section can be operated at the lower rate. The Magnitude Response is improved by using cosine prefilters which can also be moved to a lower rate. The sharpening technique is applied to all but the first comb section. The resulting structure is multiplier-free, does not have any filtering at the high input rate, and the Magnitude Response has a low passband droop and high stopband attenuation. 1
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a new multistage comb modified rotated sinc rs decimator with sharpened Magnitude Response
IEICE Transactions on Information and Systems, 2005Co-Authors: Gordana Jovanovic Dolecek, S K MitraAbstract:This paper presents a new multistage comb-rotated sinc (RS) decimator with a sharpened Magnitude Response. Novelty of this paper is that the multistage structure has more design parameters that provides additional flexibility to the design procedure. It uses different sharpening polynomials and different cascaded comb filters at different stages. As the comb filters at the latter stages are of lower order than that of the original comb filter, the use of more complex sharpening polynomials at latter stages is possible. This leads to an improvement of the frequency characteristic without a significant increase in the complexity of the overall filter. The comb filter of the first stage is realized in a non-recursive form and can be implemented in a computationally efficient form by making use of the polyphase decomposition of the transfer function in which the subfilters operate at a lower rate that depends on the down-sampling factor employed in the first stage. In addition, both multipliers of the rotated sinc (RS) filter of the second stage work at a lower rate.
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efficient multistage comb modified rotated sinc rs decimator
European Signal Processing Conference, 2004Co-Authors: G Jovanovicdolecek, S K MitraAbstract:This paper presents a new multistage comb-rotated sinc (RS) decimator. The proposed structure consists of different cascaded comb sections, each down-sampled by a specific down-sampling factor. The number of sections depends on the decimation factor of the original comb decimator. The first section is realized in a non-recursive form. Using the polyphase decomposition, the sub-filters of the first section can be operated at lower rate which depends on the down-sampling factor of the first section. Additionally, the rotated sinc (RS) filter is cascaded in the second section, thus permitting both multipliers of the RS filter to work at the lower rate. The Magnitude Response of the proposed structure is better than that of the original comb decimator.
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efficient comb rotated sinc rs decimator with sharpened Magnitude Response
Midwest Symposium on Circuits and Systems, 2004Co-Authors: Gordana Jovanovic Dolecek, S K MitraAbstract:This paper presents a comb-rotated sine (RS) decimator with a sharpened Magnitude Response. The decimator is composed of two main sections. The first section is a cascaded comb decimator, while the second section is a cascade of a sharpened comb and a rotated sine (RS) decimator. Using the polyphase decomposition, the subfilters of the first section can be operated at lower rate, which depends on the down-sampling factor of the first section. Additionally, as the RS filter is in the second section, both multipliers of the RS filter work at the lower rate. The Magnitude Response of the proposed filter is improved by using the sharpened technique in the second section.
B A Wooley - One of the best experts on this subject based on the ideXlab platform.
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a cmos oversampled dac with multi bit semi digital filtering and boosted subcarrier snr for adsl central office modems
IEEE Journal of Solid-state Circuits, 2006Co-Authors: A C Y Lin, R K Hester, B A WooleyAbstract:An oversampled digital-to-analog converter for use in ADSL central office modems has been integrated in 0.18-/spl mu/m CMOS technology. The converter features a multi-bit semi-digital filter for reconstruction and a digital pre-emphasis filter that boosts the SNR of subcarriers affected by noise shaping and flattens the overall in-band Magnitude Response. A resampled impulse Response is employed to simplify the implementation of the semi-digital filter. The combination of digital and semi-digital filtering allows the design to meet all ADSL performance requirements with only 180 current cells and a third-order analog low-pass reconstruction filter. When sampling at 200 MSample/s, the converter achieves 86-dB dynamic range for a 1.1-MHz bandwidth, with an average MTPR of 65 dB.
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a cmos oversampling d a converter with multi bit semi digital filtering and boosted subcarrier snr for adsl central office modems
Symposium on VLSI Circuits, 2005Co-Authors: A C Y Lin, R K Hester, B A WooleyAbstract:An oversampling D/A converter for use in ADSL central office modems has been integrated in 0.18-/spl mu/m CMOS technology. The converter features a resampled, multibit semidigital filter for reconstruction and a digital pre-emphasis filter that flattens the overall in-band Magnitude Response and boosts the SNR of subcarriers affected by noise shaping. When sampling at 200 MHz, the converter achieves 86 dB of dynamic range for a 1.1-MHz bandwidth, with an average MTPR of 73dBc.
A C Y Lin - One of the best experts on this subject based on the ideXlab platform.
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a cmos oversampled dac with multi bit semi digital filtering and boosted subcarrier snr for adsl central office modems
IEEE Journal of Solid-state Circuits, 2006Co-Authors: A C Y Lin, R K Hester, B A WooleyAbstract:An oversampled digital-to-analog converter for use in ADSL central office modems has been integrated in 0.18-/spl mu/m CMOS technology. The converter features a multi-bit semi-digital filter for reconstruction and a digital pre-emphasis filter that boosts the SNR of subcarriers affected by noise shaping and flattens the overall in-band Magnitude Response. A resampled impulse Response is employed to simplify the implementation of the semi-digital filter. The combination of digital and semi-digital filtering allows the design to meet all ADSL performance requirements with only 180 current cells and a third-order analog low-pass reconstruction filter. When sampling at 200 MSample/s, the converter achieves 86-dB dynamic range for a 1.1-MHz bandwidth, with an average MTPR of 65 dB.
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a cmos oversampling d a converter with multi bit semi digital filtering and boosted subcarrier snr for adsl central office modems
Symposium on VLSI Circuits, 2005Co-Authors: A C Y Lin, R K Hester, B A WooleyAbstract:An oversampling D/A converter for use in ADSL central office modems has been integrated in 0.18-/spl mu/m CMOS technology. The converter features a resampled, multibit semidigital filter for reconstruction and a digital pre-emphasis filter that flattens the overall in-band Magnitude Response and boosts the SNR of subcarriers affected by noise shaping. When sampling at 200 MHz, the converter achieves 86 dB of dynamic range for a 1.1-MHz bandwidth, with an average MTPR of 73dBc.
G.k. Singh - One of the best experts on this subject based on the ideXlab platform.
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A new method for higher-order linear phase FIR digital filter using shifted Chebyshev polynomials
Signal Image and Video Processing, 2016Co-Authors: S. Suman, A. Kumar, G.k. SinghAbstract:In this work, a new method for the design of linear phase finite impulse Response (FIR) filters using shifted Chebyshev polynomial is proposed. In this method, Magnitude Response of FIR filter is approximated with the help of shifted Chebyshev polynomials. The number of polynomials used for approximation depends upon the order of filter. Design problem of filter is constructed as minimization of integral mean-square error between the ideal Response and actual Response through differentiating it with respect to its coefficients, which leads to a system of linear equations. The simulation results included in this paper show the efficiency of proposed method. It is also evident from the results that the proposed method is suitable for higher filter taps.
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an improved particle swarm optimization method for multirate filter bank design
Journal of The Franklin Institute-engineering and Applied Mathematics, 2013Co-Authors: Shaik Mohammad Rafi, Anil Kumar, G.k. SinghAbstract:Abstract In this paper, a new particle swarm optimization (PSO) based method is proposed for the design of a two-channel linear phase quadrature mirror filter (QMF) bank in frequency domain. The origional particle swarm optimization technique is modified by introducing the concept of Scout Bee from Artificial Bee Colony (ABC) technique for designing a low pass prototype filter having ideal filter characteristics in the passband and stopband regions, and its Magnitude Response at quadrature frequency is 0.707. The design problem is formulated as a linear combination of passband error and residual stop band energy of the low pass filter, and the square error of the overall transfer function of the QMF bank at the quadrature frequency π/2, in the transition band. The design results included in the paper clearly show the improvement of the proposed PSO technique over earlier reported results.
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Near Perfect Reconstruction Quadrature Mirror Filter
2011Co-Authors: A. Kumar, G.k. SinghAbstract:Abstract—In this paper, various algorithms for designing quadrature mirror filter are reviewed and a new algorithm is presented for the design of near perfect reconstruction quadrature mirror filter bank. In the proposed algorithm, objective function is formulated using the perfect reconstruction condition or Magnitude Response condition of prototype filter at frequency (ω = 0.5π) in ideal condition. The cutoff frequency is iteratively changed to adjust the filters coefficients using optimization algorithm. The performances of the proposed algorithm are evaluated in term of computation time, reconstruction error and number of iterations. The design examples illustrate that the proposed algorithm is superior in term of peak reconstruction error, computation time, and number of iterations. The proposed algorithm is simple, easy to implement, and linear in nature. Keywords—Aliasing cancellations filter bank, Filter banks, quadrature mirror filter (QMF), subband coding. I
Alan E Willner - One of the best experts on this subject based on the ideXlab platform.
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true time delays using conversion dispersion with flat Magnitude Response for wideband analog rf signals
Optics Express, 2012Co-Authors: Omer F Yilmaz, Lior Yaron, Salman Khaleghi, Reza M Chitgarha, Moshe Tur, Alan E WillnerAbstract:We demonstrate optical true time delays using wavelength conversion coupled with chromatic dispersion. The transfer function of the delay system is investigated, and it is shown that 3-dB bandwidth of the system can be increased over 40 GHz by using offset pumps. A flat Magnitude Response ( 30 dB peak-to-sidelobe-ratio. The effect of pump depletion during wavelength conversion is also investigated.
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true time delays using conversion dispersion with flat Magnitude Response for wideband analog rf signals
European Conference on Optical Communication, 2011Co-Authors: Omer F Yilmaz, Lior Yaron, Salman Khaleghi, Reza M Chitgarha, Moshe Tur, Alan E WillnerAbstract:We demonstrate optical true time delays using wavelength conversion coupled with chromatic dispersion. Using offset pumps, < 1 dB Magnitude Response fluctuations over ∼40 GHz of bandwidth is achieved. Calculated linear frequency-modulated impulse Response maintains a <-32 dB peak-to-sidelobe-ratio.
