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This introductory chapter on discrete-time signal processing deals with sampled-data filters and networks as represented, for example, by switched-capacitor filters. In contrast to digital filters, which are quantized in time and... more
This introductory chapter on discrete-time signal processing deals with sampled-data filters and networks as represented, for example, by switched-capacitor filters. In contrast to digital filters, which are quantized in time and amplitude, sampled-data networks are quantized only in time. This quantization in time is achieved by sampling the analog signal at regular intervals, the sampling frequency.
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A method for the direct, by-inspection analysis of general switched-capacitor networks using signal-flow graph techniques is presented. Compared to previous methods by the authors, which were restricted to stray-insensitive networks, the... more
A method for the direct, by-inspection analysis of general switched-capacitor networks using signal-flow graph techniques is presented. Compared to previous methods by the authors, which were restricted to stray-insensitive networks, the method has been generalized to encompass all possible SC networks, including biphase- and multiphase networks, networks with unity-gain buffers, and differential amplifiers.
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... Low-Pass Filter with Combined Anti-Aliasing Decimation Filter for Low Frequencies DANIEL C. VON GR~IGEN, RAINER SIGG, MICHAEL LUDWIG, URS W. BRUGGER, MEMBER, IEEE, GEORGE S. MOSCHYTZ, FELLOW, IEEE, AND HANS MELCHIOR ...
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A complete automated development system for up to 16th-order semicustom switched-capacitor (SC) filters is presented. A unique synthesis and design methodology is used which leads to simple and regular SC structures that are defined by a... more
A complete automated development system for up to 16th-order semicustom switched-capacitor (SC) filters is presented. A unique synthesis and design methodology is used which leads to simple and regular SC structures that are defined by a single unique metal layer on a CMOS gate-array-type filter chip. Two high-order ladder filters and a cascaded biquad filter have been designed and implemented
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In the paper, the minimisation of the gain-sensitivity product (g.s.p.) for two important active-filter types that are finding widespread use in voiceband communication systems, in the form of hybrid-integrated filter building blocks, is... more
In the paper, the minimisation of the gain-sensitivity product (g.s.p.) for two important active-filter types that are finding widespread use in voiceband communication systems, in the form of hybrid-integrated filter building blocks, is considered. The first comprises a twin I for zero realisation: this is incorporated in the positive-feedback loop of a single operational amplifier and is referred to as the twin-T s.a.b.b. The known conditions for minimum g.s.p. for the twin-T s.a.b.b. are briefly recapitulated and expanded. The second comprises a differential scheme for zero realisation, and combines positive and negative feedback. It is referred to as the single-amplifier biquad (s.a.b.). The paper shows that the two circuits are closely related by the complementary transformation, and that conditions for minimum g.s.p. in both cases are identical
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In this paper we examine the influence of coupling to reduce the sensitivity to component tolerances in a CMOS-CCII realization of a fourth-order band-pass filter using two two-integrator biquads: cascaded and coupled. It is shown how the... more
In this paper we examine the influence of coupling to reduce the sensitivity to component tolerances in a CMOS-CCII realization of a fourth-order band-pass filter using two two-integrator biquads: cascaded and coupled. It is shown how the CCII non-idealities, causing lossy integrators, influence the coupled biquad design. With the example of a fourth-order 1MHz/100kHz band-pass filter, the design is tested with post-layout simulations with AMS 0.35-micron technology using Cadence. The analysis of the performance of both filters is done with Cadence. It is demonstrated that the coupled biquads, although having one more CCII and a resistor, have significantly lower sensitivity to component tolerances than the equivalent biquad cascade.
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— This paper presents an optimum tuning procedure for high-order low-pass (LP) elliptic filters. Since elliptic filters are often used to satisfy very tight specifications, they often need to be tuned accurately. In this paper, we... more
— This paper presents an optimum tuning procedure for high-order low-pass (LP) elliptic filters. Since elliptic filters are often used to satisfy very tight specifications, they often need to be tuned accurately. In this paper, we describe the tuning of one biquad, the 'tuning biquad', in a cascade of biquads. It is shown by Matlab simulations that the best choice for the tuning biquad consists of the pole pair with the highest pole Q ('maximum-Q poles') combined with the zero pair with the lowest frequency ('minimum-frequency zeros'). We also show how standard tuning procedures, such as those for the Tow-Thomas biquad, lead to excellent results. As an example, the tuning procedure is performed on a normalized seventh-order elliptic LP filter. I.
In this paper the design of fourth-order band-pass (BP) active-RC filters using a modified lowpass to band-pass (LP-BP) frequency transformation, applied to a second-order low-pass (LP) filter as a prototype, is presented. It is shown... more
In this paper the design of fourth-order band-pass (BP) active-RC filters using a modified lowpass to band-pass (LP-BP) frequency transformation, applied to a second-order low-pass (LP) filter as a prototype, is presented. It is shown that a BP filter can be realized by substitution of resistors and capacitors of the ladder in the low-pass prototype filter, by serial and parallel RC circuits in the resulting BP structure. Such a substitution results from a so-called, “lossy” LP-BP transformation. The design procedure is simple, and the closed-form design equations, starting from the specifications of a 4-order BP filter, are presented. A complete step-by-step design procedure is verified on a Chebyshev filter example and double-checked using PSPICE.
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The recognition 01acoustical signals and the enhancement 01speech both play an important role in many communication and signal processing systems. With the increasing portability of these systems, solutions which provide reliable... more
The recognition 01acoustical signals and the enhancement 01speech both play an important role in many communication and signal processing systems. With the increasing portability of these systems, solutions which provide reliable operation in various acoustical environments are of particular interest. In the present thesis, hidden Markov models (HMM) are shown to be a powerful tool for dealing with the areas mentioned above, approaching them as statistical detection and estimation problems, and putting them on asolid mathematical foundation. Based on this, methods and applications of HMMbased signal detection and estimation for block processing systems are presented. In the area of acoustical signal recognition, automatie speech recognition systems are the most common application. Since the performance of such systems can decrease significantly in noisy environments, robustness against background noise plays an important role. For single word recognition, this thesis gives a contrib...
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Research Interests: Engineering and IEEE
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In order to find the mechanisms responsible for the development of chronic neck pain caused by repetitive finger or arm movements, the long-term activation of motor units need to be studied. This requires intramuscular EMG long-term... more
In order to find the mechanisms responsible for the development of chronic neck pain caused by repetitive finger or arm movements, the long-term activation of motor units need to be studied. This requires intramuscular EMG long-term recordings. However, existing electromyogram (EMG signal) decomposition algorithms are restricted to short registration periods. In this paper, we present a decomposition algorithm capable of
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The decomposition of intramuscular myoelectric (EMG) signals can be considered as a classification problem. The main effects which decrease the classification performance are Motor Unit Action Potential (MUAP) shimmer and overlapping... more
The decomposition of intramuscular myoelectric (EMG) signals can be considered as a classification problem. The main effects which decrease the classification performance are Motor Unit Action Potential (MUAP) shimmer and overlapping MUAPs. In this paper we show how time-frequency information can be extracted to reduce MUAP shimmer and propose a criterion to detect overlapping MUAPs. Because of the information extraction
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Discrete-time CNNs (DTCNNs) have been considered along with continuous-time CNNs (CTCNNs) both in terms of theory [45] and implementation as sampled-data systems [46]. The most common DTCNN is described by $$ {x_{ij}}\left[ {k + 1}... more
Discrete-time CNNs (DTCNNs) have been considered along with continuous-time CNNs (CTCNNs) both in terms of theory [45] and implementation as sampled-data systems [46]. The most common DTCNN is described by $$ {x_{ij}}\left[ {k + 1} \right] = \sum\limits_{mn \in {N_{ij}}} {{a_{mn}}\operatorname{sgn} \left( {{x_{mn}}\left[ k \right]} \right) + \sum\limits_{mn \in {N_{ij}}} {{b_{mn}}{u_{mn}} + I} } $$ (5.1) .
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Research Interests: Engineering and IEEE
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ABSTRACT In this paper it is shown that active-RC filters whose sensitivity to component tolerances can be minimized by impedance tapering, will also have low output thermal noise. It is shown that impedance tapering will also reduce... more
ABSTRACT In this paper it is shown that active-RC filters whose sensitivity to component tolerances can be minimized by impedance tapering, will also have low output thermal noise. It is shown that impedance tapering will also reduce output thermal noise in OTA-C filters. Copyright © 2010 John Wiley & Sons, Ltd. (This work was partially supported by the Ministry of Science, Education and Sports of Republic of Croatia.)
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ABSTRACT SUMMARY A new and straightforward design procedure for simple canonical topologies of allpole, active-RC, low-selectivity band-pass (BP) filters, with low sensitivity to component tolerances is presented. The procedure is... more
ABSTRACT SUMMARY A new and straightforward design procedure for simple canonical topologies of allpole, active-RC, low-selectivity band-pass (BP) filters, with low sensitivity to component tolerances is presented. The procedure is primarily intended for discrete-component, low-power filter applications using just one amplifier for relatively high-order filters. The design procedure starts out with an ‘optimized’ low-pass (LP) prototype filter, yielding an ‘optimized’ BP filter, whereby the wealth of ‘optimized’ single-amplifier LP filter designs can be exploited. Using a so-called ‘lossy’ LP–BP transformation, closed-form design equations for the design of second- to eighth-order, single-amplifier BP filters are presented. The low sensitivity, low power consumption, and low noise features of the resulting circuits, as well as the influence of the finite gain-bandwidth product and component spread, are demonstrated for the case of a fourth-order filter example. The optimized single-opamp fourth-order filter is compared with other designs, such as the cascade of optimized Biquads. Using PSpice with a TL081 opamp model, the filter performance is simulated and the results compared and verified with measurements of a discrete-component breadboard filter using 1% resistors, 1% capacitors, and a TL081 opamp. Copyright © 2011 John Wiley & Sons, Ltd.
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Research Interests: Computer Science, Distributed Computing, Impedance Matching, Reduction, Impedance, and 10 moreCircuits, Frequency Range, Digital Subscriber Line, Transmitter, Highspeed Data for Subscriber Lines, Electrical And Electronic Engineering, Quadrature Amplitude Modulation, Data Transmission, RC network, and RC Circuit
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Abstract- In this paper the design of fourth-order band-pass (BP) active-RC filters using a modified low-pass to band-pass (LP-BP) frequency transformation, applied to a second-order low-pass (LP) filter as a prototype, is presented. It... more
Abstract- In this paper the design of fourth-order band-pass (BP) active-RC filters using a modified low-pass to band-pass (LP-BP) frequency transformation, applied to a second-order low-pass (LP) filter as a prototype, is presented. It is shown that a BP filter can be realized by substitution of resistors and capacitors of the ladder in the low-pass prototype filter, by serial and parallel RC circuits in the resulting BP structure. Such a substitution results from a so-called, “lossy ” LP-BP transformation. The design procedure is simple, and the closed-form design equations, starting from the specifications of a 4th-order BP filter, are presented. A complete step-by-step design procedure is verified on a Chebyshev filter example and double-checked using PSPICE.. 1
An all-analog high-speed decoding technique is described which is suitable for magnetic recording (MR) and other computationally demanding applications. A decoder for a binary (18,9,5) tail-biting trellis code, which is much simpler than... more
An all-analog high-speed decoding technique is described which is suitable for magnetic recording (MR) and other computationally demanding applications. A decoder for a binary (18,9,5) tail-biting trellis code, which is much simpler than the codes used for MR, has been chosen to demonstrate this technique. It achieves a decoding rate of 100 Mbit/s at a single 5V power supply. The power consumption is 50mW. Higher speed can essentially be traded for higher power consumption. A comparison shows that a digital implementation is outperformed by more than two orders of magnitude in terms of speed and/or power consumption.
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In adaptive noise cancelling, linear digital filters have been used to minimize the mean squared difference between filter outputs and the desired signal. However, for non-Gaussian probability density functions of the involved signals,... more
In adaptive noise cancelling, linear digital filters have been used to minimize the mean squared difference between filter outputs and the desired signal. However, for non-Gaussian probability density functions of the involved signals, nonlinear filters can further reduce the mean squared difference, thereby improving the signal-to-noise ratio at the system output. This is illustrated with a two-microphone beamformer for cancelling directional interference. In the case of a single uniformly distributed interference, we establish the optimum nonlinear performance limit. To approximate optimum performance, we realize two nonlinear filter architectures, the Volterra filter and the multilayer perceptron. The Volterra filter is also examined for speech interference. The beamformer is adapted to minimize the mean squared difference, but performance is measured with the intelligibility weighted gain. This criterion requires the signal-to-noise ratio at the beamformer output. For the nonlinear processor, this can only be determined when no target components exist in the reference channel of the noise canceller so that the target is transmitted without distortion. Under these ideal conditions and at equal filter lengths, the quadratic Volterra filter improves the intelligibility-weighted gain by maximally 2 dB relative to the linear filter