Wave Digital Modeling and Implementation of Nonlinear Audio Circuits With Nullors

Giampiccolo, Riccardo; Bari, Mauro Giuseppe de; Bernardini, Alberto; Sarti, Augusto

doi:10.1109/taslp.2021.3120627

Cited by 11 publications

(5 citation statements)

References 26 publications

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“…In [22], stamps are provided for encompassing nullors into scattering junctions by means of the Modified Nodal Analysis (MNA) formalism. The same result is reached in a more efficient fashion considering a double digraph decomposition of the connection network, as pointed out in [23]. In [25], vector waves are used to derive a vectorial scattering relation that allows to implement a nullor as a two-port input-output element in the WD domain.…”

Section: Introductionmentioning

confidence: 57%

“…In this work, we use Wave Digital Filters (WDFs) [21] since they proved to be suitable for an efficient implementation of both direct and inverse models of loudspeakers [16,17]. In particular, elements and topological interconnections can be realized as explained in [24], whereas nullors are encompassed into the scattering junction exploiting the double digraph decomposition of connection networks presented in [23]. Then, being the circuit linear, the Wave Digital (WD) structure can be solved with no iterative solvers by means of traditional techniques [21].…”

Section: Sensor Virtualization: Application To Capacitive Microphonesmentioning

confidence: 99%

“…WDF theory was originally introduced by A. Fettweis in the late 1970s for designing stable digital filters through the discretization of linear passive analog filters [21], and was later extended to also efficiently implement active and nonlinear circuits in the discrete-time domain [22][23][24]. In the WDF framework, port voltages and port currents are substituted with linear combinations of incident and reflected waves introducing a free parameter per port called port resistance.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

On the Virtualization of Audio Transducers

Giampiccolo

Bernardini

Massi

et al. 2023

Sensors

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In audio transduction applications, virtualization can be defined as the task of digitally altering the acoustic behavior of an audio sensor or actuator with the aim of mimicking that of a target transducer. Recently, a digital signal preprocessing method for the virtualization of loudspeakers based on inverse equivalent circuit modeling has been proposed. The method applies Leuciuc’s inversion theorem to obtain the inverse circuital model of the physical actuator, which is then exploited to impose a target behavior through the so called Direct–Inverse–Direct Chain. The inverse model is designed by properly augmenting the direct model with a theoretical two-port circuit element called nullor. Drawing on this promising results, in this manuscript, we aim at describing the virtualization task in a broader sense, including both actuator and sensor virtualizations. We provide ready-to-use schemes and block diagrams which apply to all the possible combinations of input and output variables. We then analyze and formalize different versions of the Direct–Inverse–Direct Chain describing how the method changes when applied to sensors and actuators. Finally, we provide examples of applications considering the virtualization of a capacitive microphone and a nonlinear compression driver.

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Section: Introductionmentioning

confidence: 57%

Section: Sensor Virtualization: Application To Capacitive Microphonesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Virtualization of Audio Transducers

Giampiccolo

Bernardini

Massi

et al. 2023

Sensors

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“…In the WD domain, a N -port connection network is modeled as a N -port junction characterized by a N × N scattering matrix S such that b = Sa, where a = v + Zi is the vector of waves incident to the junction, b = v − Zi is the vector of waves reflected from the junction, v is the vector of port voltages, i is the vector of port currents and Z is a diagonal matrix containing the free parameters [45,40,46,47].…”

Section: Wd Modeling Of Connection Networkmentioning

confidence: 99%

Loudspeaker virtualization–Part I: Digital modeling and implementation of the nonlinear transducer equivalent circuit

Bernardini

Bianchi²,

Sarti

2023

Signal Processing

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“…Introduced for the analysis of large photovoltaic arrays under partial shading conditions, SIM is able to solve generic circuits containing multiple nonlinear one-ports using independent one-dimensional solvers. SIM was extended for the discrete-time domain emulation of diode-based ring modulators in the context of VA modeling [12,20], and then employed for the emulation of many other audio circuits [21][22][23][24]. It is worth adding that, in the WD domain, a proper choice of the free parameters has a direct effect not only on the speed of convergence of fixedpoint methods, but also of WD Newton-Raphson methods, as discussed in [25].…”

Section: Introductionmentioning

confidence: 99%

Parallel Wave Digital Filter Implementations of Audio Circuits with Multiple Nonlinearities

Giampiccolo¹,

Natoli²,

Bernardini³

et al. 2022

J. Audio Eng. Soc.

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Modern audio systems and musical effects feature multi-core processing units. The development of parallel audio processing algorithms capable of exploiting the architecture of such hardware is thus in order. In this paper, we present a parallel version of the Hierarchical Scattering Iterative Method (HSIM), a technique based on Wave Digital Filter principles recently proposed for the emulation of multiphysics audio circuits containing multiple nonlinear oneports and nonlinear transformers. HSIM operates in a modular fashion, and it is characterized by a high number of embarrassingly parallelizable operations, making it a good candidate for parallel execution. After analyzing HSIM from the parallel computing perspective, we propose three different strategies for the distribution of HSIM workload among threads of execution, and we show how to compute the maximum achievable speedup. The emulation of a possible output stage of a vacuum-tube guitar amplifier is considered, and a performance comparison between parallel and serial implementations of HSIM is presented, pointing out a speedup of nearly 30%. The proposed method proves thus to be promising for Virtual Analog modeling applications, leading the way towards the parallel digital emulation of increasingly complex audio circuits.

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Wave Digital Modeling and Implementation of Nonlinear Audio Circuits With Nullors

Cited by 11 publications

References 26 publications

On the Virtualization of Audio Transducers

On the Virtualization of Audio Transducers

Loudspeaker virtualization–Part I: Digital modeling and implementation of the nonlinear transducer equivalent circuit

Parallel Wave Digital Filter Implementations of Audio Circuits with Multiple Nonlinearities

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