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18
On the Stability of Sigma Delta Modulators
 IEEE TRANSACTLONS ON SIGNAL PROCESSING, VOL. 41. NO. 7. JULY 1993
, 1993
"... In this paper we propose a framework for stability analysis of EA modulators, and argue that limit cycles for constant inputs are natural objects to investigate in this context. We present a number of analytical and approximate techniques to aid the stability analysis of the double loop and interpol ..."
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Cited by 19 (2 self)
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In this paper we propose a framework for stability analysis of EA modulators, and argue that limit cycles for constant inputs are natural objects to investigate in this context. We present a number of analytical and approximate techniques to aid the stability analysis of the double loop and interpolative modulators, and use these techniques to propose ways of improved design that explicitly take stability into account.
Reconstruction of oversampled bandlimited signals from sigma delta encoded binary sequences
 IEEE Transactions on Signal Processing
, 1994
"... AbstractWe consider the application of EA modulators to analogtodigital conversion. We have previously shown that for constant input signals, optimal nonlinear decoding can achieve large gains in signaltonoise ratio (SNR) over linear decoding. In this paper we show a similar result for bandlimi ..."
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Cited by 11 (1 self)
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AbstractWe consider the application of EA modulators to analogtodigital conversion. We have previously shown that for constant input signals, optimal nonlinear decoding can achieve large gains in signaltonoise ratio (SNR) over linear decoding. In this paper we show a similar result for bandlimited input signals. The new nonlinear decoding algorithm is based on projections onto convex sets (POCS), and alternates between a timedomain operation and a band limitation to find a signal invariant under both. The timedomain operation results in a quadratic programming problem. The band limitation can be based on singular value decomposition of a certain matrix. We show simulation results for the SNR.performance of a POCSbased decoder and a linear decoder for the single loop, double loop and twostage CA modulators and for a specific fourthorder interpolative modulator. Depending on the modulator and the oversampling ratio, improvements in SNR of up to 1&20 dB can be achieved. I.
Deltasigma cellular automata for analog VLSI random vector generation
 IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, Vol.46, No.3
, 1999
"... Abstract—We present a class of analog cellular automata for parallel analog random vector generation, including theory on the randomness properties, scalable parallel very large scale integration (VLSI) architectures, and experimental results from an analog VLSI prototype with 64 channels. Linear co ..."
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Cited by 2 (0 self)
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Abstract—We present a class of analog cellular automata for parallel analog random vector generation, including theory on the randomness properties, scalable parallel very large scale integration (VLSI) architectures, and experimental results from an analog VLSI prototype with 64 channels. Linear congruential coupling between cells produces parallel channels of uniformly distributed random analog values, with statistics that are uncorrelated both across channels and over time. The cell for each random channel essentially implements a switchedcapacitor delta–sigma modulator, and measures 100 m 2 120 min2 m CMOS technology. The 64 cells are connected as a MASH cascade in a chain or ring topology on a twodimensional (2D) grid, and can be rearranged for use in various VLSI applications that require a parallel supply of random analog vectors, such as analog encryption and secure communications, analog builtin selftest, stochastic neural networks, and simulated annealing optimization and learning. Index Terms—Random generation, noise, delta–sigma modulation, cellular automata, analog VLSI, neural networks, switchedcapacitor circuits.
Estimating from Outputs of Oversampled DeltaSigma Modulation
"... . Oversampling a deltasigmamodulated sequence, one can compute unbiased sample estimates of averages of consecutive input elements for a wide variety of inputs. We prove that these estimates are most efficient in their class (that is, variances of sample means are minimum in the class of random bi ..."
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Cited by 1 (0 self)
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. Oversampling a deltasigmamodulated sequence, one can compute unbiased sample estimates of averages of consecutive input elements for a wide variety of inputs. We prove that these estimates are most efficient in their class (that is, variances of sample means are minimum in the class of random binary sequences g n , n = 1; : : : ; N , such that the expected values of g n are equal to the values of the corresponding inputs of deltasigma modulation) and consistent. Deltasigma modulation may also be described as onedimensional error diffusion (a technique for digital halftoning). However, deltasigma modulation is not a practical digital halftoning algorithm, because human vision averages small luminance deviations in two dimensions. We pose an open problem that invites the reader to extend our approach to the twodimensional case for the purpose of development of a practical digital halftoning algorithm. IEEE EDICS number: SP 3.8.2 Correspondence should be sent to: Dmitri A. Guse...
A Design Technique for Polyphase Decimators with Binary Constrained Coefficients for High Resolution A/D Converters
, 1994
"... ..."
System on Chip FPGA Design of an FM Demodulator using a Kalman BandPass SigmaDelta Architecture
"... Abstract — In this paper, an efficient architecture for Kalman bandpass SigmaDelta (Σ∆) demodulator used in the application of FM demodulation is presented. The IF stage of the circuit separates the inphase and quadrature (I and Q) signals using a single circuit path, thus eliminating IQ differe ..."
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Cited by 1 (0 self)
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Abstract — In this paper, an efficient architecture for Kalman bandpass SigmaDelta (Σ∆) demodulator used in the application of FM demodulation is presented. The IF stage of the circuit separates the inphase and quadrature (I and Q) signals using a single circuit path, thus eliminating IQ differences due to component mismatch. The separated IQ signals are then filtered using an efficient recursive Kalman bandpass filter. The completed FM demodulator system is designed and implemented in hardware using FPGA (Field Programmable Gate Array). The flexible and programmable system on chip FM demodulator is described. The synthesis results of the FPGA design is reported. I.
Quantization Errors of fGn and fBm Signals
 IEEE Signal Processing Letters
"... In this Letter, we show that under the assumption of high resolution, the quantization errors of fGn and fBm signals with uniform quantizer can be treated as uncorrelated white noises. 1 ..."
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In this Letter, we show that under the assumption of high resolution, the quantization errors of fGn and fBm signals with uniform quantizer can be treated as uncorrelated white noises. 1
iii To the Memory of Eugene A. Sandler iv Acknowledgments
, 1999
"... James T. Newkirk for their help and advice. Thomas Zeggel provided the code of his iterative convolution algorithm, and Vladimir Me~nkov helped me to incorporate it in myworking environment. Reg Heron taught me to use the re ection densitometer and helped with the density measurements. Jun Li made a ..."
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James T. Newkirk for their help and advice. Thomas Zeggel provided the code of his iterative convolution algorithm, and Vladimir Me~nkov helped me to incorporate it in myworking environment. Reg Heron taught me to use the re ection densitometer and helped with the density measurements. Jun Li made a black mask for the luminance measurements and conducted the subjective rating experiment. I am deeply grateful to Gregory Pogosyants for his permission to use the digitized portrait of his daughter, Anya Pogosyants (1969{1995), who was a computer science Ph.D. student at the
AntiCorrelation Digital Halftoning
"... A new class of digital halftoning algorithms is introduced. Anticorrelation digital halftoning (ACDH) combines the idea of a wellknown game, Russian roulette, with the statistical approach to bilevel quantization of digital images. A representative ofthe class, serpentine anticorrelation digital h ..."
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A new class of digital halftoning algorithms is introduced. Anticorrelation digital halftoning (ACDH) combines the idea of a wellknown game, Russian roulette, with the statistical approach to bilevel quantization of digital images. A representative ofthe class, serpentine anticorrelation digital halftoning, is described and compared to error di usion, ordered dither, and other important digital halftoning techniques. Serpentine ACDH causes fewer unpleasant correlated artifacts and less contouring than the benchmark algorithms. The quantization noise spectra associated with serpentine ACDH possess bene cial characteristics related to properties of the vision system. The term \violet noise " is proposed to describe quantization noise with stronger bias in favor of highfrequency components than that of blue noise. Novel techniques for color visualization of the noise spectra and the corresponding phase spectra are introduced, and the relative signi cance of the magnitudes and phases of the discrete Fourier transform of the quantization noise is studied. Unlike popular algorithms based on error di usion, serpentine ACDH does not enhance edges. This is good for applications to digital holography and medical imaging. A simple input preprocessing technique allowsonetointroduce edge enhancement if desired, while keeping it more isotropic than that of error di usion. The relation between unwanted transient boundary e ects and edge enhancement accompanying error di usion is examined, and approaches to reduction of boundary e ects are considered. Serpentine ACDH does not cause signi cant boundary e ects. The average intensity representation by di erent algorithms is studied for constant input levels (serpentine ACDH does remarkably well). Prospects for ACDH research are discussed.