Wave Field Simulation with the Functional Transformation Method

Petrausch, Stefan; Rabenstein, Rudolf

doi:10.1109/icassp.2006.1661276

Cited by 11 publications

(10 citation statements)

References 6 publications

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“…18 Compared to the FTM, very few, almost negligible, differences have been found. It must be taken into account that FTM is free of dispersion, 6 and for the presented examples, the FDTD mesh has been selected for a low level of dispersion because oversampling has been used. In summary, efficacy of the proposed algorithm is independent of the discrete-time method used.…”

Section: Resultsmentioning

confidence: 99%

“…According to this, a mesh of discretized spatial points represents the sound field for a given time step. Among different paradigms in the discrete-time domain applied to the room acoustic problems, the most frequently used methods are the finite-difference time-domain 3 (FDTD), digital waveguide mesh 4 (DWM), transmission line matrix 5 (TLM), and the recently proposed functional transformation method 6 (FTM). The initial conditions for these methods are uniquely expressed as a distribution of monopoles (pressure sources), and dipoles (particle velocity sources) particularly in the case of the FDTD method; but in practical and more general problems, sources are too far to be represented as monopole or dipole sources and more complex source modeling is required.…”

Section: 2mentioning

confidence: 99%

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Directive sources in acoustic discrete-time domain simulations based on directivity diagrams

Escolano

Lopez

Pueo

2007

The Journal of the Acoustical Society of America

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Discrete-time domain methods provide a simple and flexible way to solve initial boundary value problems. With regard to the sources in such methods, only monopoles or dipoles can be considered. However, in many problems such as room acoustics, the radiation of realistic sources is directional-dependent and their directivity patterns have a clear influence on the total sound field. In this letter, a method to synthesize the directivity of sources is proposed, especially in cases where the knowledge is only based on discrete values of the directivity diagram. Some examples have been carried out in order to show the behavior and accuracy of the proposed method.

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Section: Resultsmentioning

confidence: 99%

Section: 2mentioning

confidence: 99%

Directive sources in acoustic discrete-time domain simulations based on directivity diagrams

Escolano

Lopez

Pueo

2007

The Journal of the Acoustical Society of America

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“…According to (23), the saturation operating region is also characterized by a nonlinear equation. Substituting (29) in (32) and defining the vector w as…”

Section: Saturation Operating Regionmentioning

confidence: 99%

Wave Digital Modeling of Nonlinear 3-terminal Devices for Virtual Analog Applications

Bernardini¹,

Vergani²,

Sarti³

2020

Circuits Syst Signal Process

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We propose a novel modeling method for circuits containing arbitrary nonlinear 3-terminal devices, which operates in the Wave Digital (WD) domain. This approach leads to the definition of a general and flexible WD model for 3-terminal devices, whose number of ports varies from 1 to 6. The generality of the method is confirmed by the fact that the WD models of 3terminal devices already discussed in the literature can be seen as particular cases of the model that we present here. As examples of applications of our method, we develop WD models of the three most widespread types of transistors in audio circuitry, i.e., the MOSFET, the JFET and the BJT. These models are here designed to be used in Virtual Analog audio applications, therefore their derivation is aimed at minimizing computational complexity while avoiding implicit relations between port variables, as far as possible. Proposed MOSFET and JFET models are characterized by third-order polynomial equations, hence explicit closed-form wave scattering relations are obtained. On the other hand, the Ebers-Moll model describing the BJT results in transcendental equations in the WD domain that cannot be solved analytically. In order to cope with this problem, we propose a modified Newton-Raphson (NR) method for solving the implicit Ebers-Moll equations in the WD domain. Such iterative method exhibits a significantly higher robustness and convergence rate with respect to a traditional NR method, without compromising its efficiency. Finally, WD implementations of some audio circuits containing transistors are discussed.

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“…The interconnection of elements is represented by means of adaptors [4]. Nonlinear devices (both algebraic and dynamic) can be modeled in terms of waves [5–11]. For circuits with more than one nonlinear device port, delay‐free loops (DFLs) in the wave paths are likely to be formed [6].…”

Section: Introductionmentioning

confidence: 99%

“…DFLs prevent the direct computation of waves in the circuit. Some approaches exist [10, 11] to eliminate DFLs created by multiple nonlinearities. Basically all nonlinear devices and some interconnections are lumped in a subcircuit and the reflections from its ports are precomputed given all possible combinations of incident waves.…”

Section: Introductionmentioning

confidence: 99%

Transient simulation based on state variables and waves

Kabir

Christoffersen

Kriplani

2011

Int J RF and Microwave Comp Aid Eng

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This article reports a new method for transient analysis of nonlinear circuits based on nonlinear device state variables and waves at their ports. The method is based on relaxation and thus does not require large matrix decompositions if time step is constant. The use of waves results in guaranteed convergence for any linear passive circuit and some types of nonlinear circuits. Additionally, the formulation using waves ensures that nonlinear devices are always excited with a physically meaningful input, i.e., the amount of power transmitted to nonlinear devices is bounded. The method was implemented in the fREE-DA TM circuit simulator. The formulation, its properties, and a convergence analysis of the proposed method are presented first, followed by case studies. V C 2011 Wiley Periodicals, Inc.Int J RF and Microwave CAE 21:314-324, 2011.

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Wave Field Simulation with the Functional Transformation Method

Cited by 11 publications

References 6 publications

Directive sources in acoustic discrete-time domain simulations based on directivity diagrams

Directive sources in acoustic discrete-time domain simulations based on directivity diagrams

Wave Digital Modeling of Nonlinear 3-terminal Devices for Virtual Analog Applications

Transient simulation based on state variables and waves

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