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18
Efficient Synthesis of Stringed Musical Instruments
, 1993
"... Techniques are described for reducing complexity in stringed instrument simulation for purposes of digital synthesis. These include commuting losses and dispersion to consolidate them into a single lter, replacing body resonators by lookup tables, simplied bowstring interaction, and singlelter ..."
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Cited by 52 (1 self)
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Techniques are described for reducing complexity in stringed instrument simulation for purposes of digital synthesis. These include commuting losses and dispersion to consolidate them into a single lter, replacing body resonators by lookup tables, simplied bowstring interaction, and singlelter, multiplyfree coupled strings implementation. Contents 1 Digital Waveguide Theory 2 2 The Terminated String 4 3 Simplied Body Filters 5 4 Simplied Bowed Strings 8 5 Coupled Strings 10 6 Summary 14 7 Appendix 14 1 Page 2 1 Digital Waveguide Theory This section summarizes the digital waveguide model for vibrating strings. Further details can be found in [Smith 1992]. Position y (t,x) 0 x . . . . . . 0 K String Tension e = Mass/Length Figure 1: The ideal vibrating string. The wave equation for the ideal (lossless, linear, exible) vibrating string, depicted in Fig. 1, is given by Ky 00 = y where K = string tension y = y(t; x) = linear mass density _ y...
ReducedOrder modeling of large passive linear circuits by means of the SyPVL algorithm
 in Tech. Dig. 1996 IEEE/ACM International Conference on ComputerAided Design
, 1996
"... This paper discusses the analysis of large linear electrical networks consisting of passive components, such as resistors, capacitors, inductors, and transformers. Such networks admit a symmetric formulation of their circuit equations. We introduce SyPVL, an eficient and numerically stable algorit ..."
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Cited by 42 (14 self)
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This paper discusses the analysis of large linear electrical networks consisting of passive components, such as resistors, capacitors, inductors, and transformers. Such networks admit a symmetric formulation of their circuit equations. We introduce SyPVL, an eficient and numerically stable algorithm for the computation of reducedorder models of large, linear, passive networks. SyPVL represents the specialization of the more general PVL algorithm, to symmetric problems. Besides the gain in eficiency over PVL, SyPVL also preserves the symmetry of the problem, and, as a consequence, can often guarantee the stability of the resulting reducedorder models. Moreover, these reducedorder models can be synthesized as actual physical circuits, thus facilitating compatibility with existing analysis tools. The application of SyPVL is illustrated with two interconnectanalysis examples. 1
The Elmore Delay as a Bound for RC Trees with Generalized Input Signals
 the IEEE Transactions on CAD. (Available
"... The Elmore delay is an extremely popular delay metric, particularly for RC tree analysis. The widespread usage of this metric is mainly attributable to it being the most accurate delay measure that is a simple analytical function of the circuit parameters. The only drawbacks to this delay metric are ..."
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Cited by 40 (0 self)
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The Elmore delay is an extremely popular delay metric, particularly for RC tree analysis. The widespread usage of this metric is mainly attributable to it being the most accurate delay measure that is a simple analytical function of the circuit parameters. The only drawbacks to this delay metric are the uncertainty as to whether it is an optimistic or a pessimistic estimate, and the restriction to step response delay estimation. In this paper, we prove that the Elmore delay is an absolute upper bound on the 50 % delay of an RC tree response. Moreover, we prove that this bound holds for input signals other than steps, and that the actual delay asymptotically approaches the Elmore delay as the input signal rise time increases. A lower bound on the delay is also developed using the Elmore delay and the second moment of the impulse response. The utility of this bound is for understanding the accuracy and the limitations of the Elmore delay metric as we use it for design automation. I.
DiscreteTime Adaptive Windowing for Velocity Estimation
, 2000
"... We present methods for velocity estimation from discrete and quantized position samples using adaptive windowing. Previous methods necessitate tradeoffs between noise reduction, control delay, estimate accuracy, reliability, computational load, transient preservation, and difficulties with tuning. I ..."
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Cited by 35 (6 self)
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We present methods for velocity estimation from discrete and quantized position samples using adaptive windowing. Previous methods necessitate tradeoffs between noise reduction, control delay, estimate accuracy, reliability, computational load, transient preservation, and difficulties with tuning. In contrast, a firstorder adaptive windowing method is shown to be optimal in the sense that it minimizes the velocity error variance while maximizes the accuracy of the estimates, requiring no tradeoff. Variants of this method are also discussed. The effectiveness of the proposed technique is verified in simulation and by experiments on the control of a haptic device.
Determination of worstcase aggressor alignment for delay calculation
 In Proc. of the IEEE International Conference on ComputerAided Design (ICCAD
, 1998
"... Increases in delay due to coupling can have a dramatic impact on IC performance for deep submicron technologies. To achieve maximum performance there is a need for analyzing logic stages with large complex coupled interconnects. In timing analysis, the worstcase delay of gates along a critical path ..."
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Cited by 32 (0 self)
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Increases in delay due to coupling can have a dramatic impact on IC performance for deep submicron technologies. To achieve maximum performance there is a need for analyzing logic stages with large complex coupled interconnects. In timing analysis, the worstcase delay of gates along a critical path must include the effect of noise due to switching of nearby aggressor gates. In this paper, we propose a new waveform iteration strategy to compute the delay in the presence of coupling and to align aggressor inputs to determine the worstcase victim delay. We demonstrate the application of our methodology at both the transistorlevel and celllevel. In addition, we prove that the waveforms generated in our methodology converge under typical timing analysis conditions. 1.
A partial PadéviaLanczos method for reducedorder modeling
 Linear Algebra Appl
, 1999
"... The classical Lanczos process can be used to efficiently generate Pad'e approximants of the transfer function of a given singleinput singleoutput timeinvariant linear dynamical system. Unfortunately, in general, the resulting reducedorder models based on Pad'e approximation do not preserve the s ..."
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Cited by 16 (7 self)
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The classical Lanczos process can be used to efficiently generate Pad'e approximants of the transfer function of a given singleinput singleoutput timeinvariant linear dynamical system. Unfortunately, in general, the resulting reducedorder models based on Pad'e approximation do not preserve the stability, and possibly passivity, of the original linear dynamical system. In this paper, we describe the use of partial Pad'e approximation for reducedorder modeling. Partial Pad'e approximants have a number of prescribed poles and zeros, while the remaining degrees of freedom are used to match the Taylor expansion of the original transfer function in as many leading coefficients as possible. We present an algorithm for computing partial Pad'e approximants via suitable rank1 updates of the tridiagonal matrices generated by the Lanczos process. Numerical results for two circuit examples are reported. Key words: Lanczos algorithm; Linear dynamical system; Transfer function; Stability; Passi...
EigenvalueBased Characterization and Test for Positive Realness of Scalar Transfer Functions
 IEEE Trans. Automat. Control
, 1999
"... An eigenvaluebased characterization of positive realness of transfer functions of singleinput singleoutput timeinvariant linear systems is derived. Based on this characterization, we propose efficient computational procedures to determine if a given transfer function is positive real. The input f ..."
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Cited by 14 (6 self)
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An eigenvaluebased characterization of positive realness of transfer functions of singleinput singleoutput timeinvariant linear systems is derived. Based on this characterization, we propose efficient computational procedures to determine if a given transfer function is positive real. The input for these eigenvaluebased tests is any given, not necessarily minimal, statespace representation of the linear system. Furthermore, the tests only involve standard matrix computations, such as computing eigenvalues of a matrix or a matrix pencil. Results of numerical experiments with these eigenvaluebased tests for positive realness are reported. Key words: linear system, statespace representation, transfer function, passivity, positive realness 1 Introduction Passivity is an important concept in control and circuit theory. Roughly speaking, a (linear or nonlinear) system is strictly passive if it "consumes" energy, and it is passive if it does not "deliver" energy. The concept was firs...
Timedomain approximation by iterative methods
 IEEE Transactions on Circuit Theory
, 1966
"... AbstractAn iterative procedure is presented which permits the determination of a rational transfer function in the Laplace transform variable s which is optimal with respect to given input and output timefunctions. The optimal system of a particular order is defined as the one whose output when s ..."
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Cited by 2 (0 self)
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AbstractAn iterative procedure is presented which permits the determination of a rational transfer function in the Laplace transform variable s which is optimal with respect to given input and output timefunctions. The optimal system of a particular order is defined as the one whose output when subjected to the known input function is nearest in the time integral square sense to the desired output function. The method is thus applicable to a number of problems involving the minimization of an integral square error. To illustrate the technique, a set of optimal lumpedparameter delay lines is synthesized and their characteristics investigated; the behavior and convergence of the iteration in these problems is also studied. A comparison of other iterative methods applicable to the same problems leads to the conclusion that the proposed procedure has real advantages in computational simplicity and speed of conver
Chromosome Representation through Adjacency Matrix
 in Evolutionary Circuit Synthesis”, 2002 NASA/DoD Conference on Evolvable Hardware
"... The use of adjacency matrices to the chromosome coding in evolutionary circuits techniques is proposed. The approach is shown to overcome some of the drawbacks associated with other coding schemes simplifying the implementation of the evolution process. It is particularly shown that the proposed cod ..."
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Cited by 1 (0 self)
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The use of adjacency matrices to the chromosome coding in evolutionary circuits techniques is proposed. The approach is shown to overcome some of the drawbacks associated with other coding schemes simplifying the implementation of the evolution process. It is particularly shown that the proposed coding scheme reduces considerably the generation of anomalous circuits increasing the efficiency of the overall process. Other important issues such as fault tolerance, sensitivity and robustness of the synthesized circuits are addressed 1.
Novel Adaptive DiscreteTime Velocity Estimation Techniques And Control Enhancement Of Haptic Interfaces
"... In this paper, we present new methods for velocity estimation from discrete and quantized position samples. The proposed methods are based on adaptive windowing and address the shortcomings of the previous methods which necessitate tradeoffs between noise reduction, control delay, estimate accuracy, ..."
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In this paper, we present new methods for velocity estimation from discrete and quantized position samples. The proposed methods are based on adaptive windowing and address the shortcomings of the previous methods which necessitate tradeoffs between noise reduction, control delay, estimate accuracy, reliability, computational load, transient preservation, and difficulties with tuning. In particular, first order adaptive windowing method is shown to be optimal in the sense that it minimizes the velocity error variance while maximizes the accuracy of the estimates. The effectiveness of the proposed techniques are verified by simulation results and also by experimental results in the control of a haptic interface. 1 Introduction Numerous control systems require online velocity estimation from discretetime position signal. Examples include velocity control of manipulators [3], [14], visual servoing [7], implementation of stiff virtual walls for force reflecting interfaces [4], and mos...