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![12 Voltage controlled resistor (VCR) stage of the 1176 LN circuit [174]. The channel of the JFET acts as a VCR forming a voltage divider with R5. Drain, gate and source terminals of the JFET are marked with D,G and S.](profile/Felix-Eichas-2/publication/342530640/figure/fig23/AS:907783868280836@1593443948132/Voltage-controlled-resistor-VCR-stage-of-the-1176-LN-circuit-174-The-channel-of-the.png)
12 Voltage controlled resistor (VCR) stage of the 1176 LN circuit [174]. The channel of the JFET acts as a VCR forming a voltage divider with R5. Drain, gate and source terminals of the JFET are marked with D,G and S.
Source publication
Digital systems gain more and more popularity in todays music industry. Musicians and producers are using digital systems because of their advantages over analog electronics. They require less physical space, are cheaper to produce and are not prone to aging circuit components or temperature variations. Furthermore, they always produce the same out...
Citations
... The current study aims at proposing a novel approach to reconstructing the mathematical model of an analog chaotic circuit and establishing a reliable way for its verification. The suggested procedure for obtaining an empirical ODE from the circuit is based on machine learning algorithms for nonlinear system identification, which have significantly advanced in the last decades [35][36][37][38][39][40]. Verification of the obtained ODE is performed via synchronization with real data following the improved procedure from [31]. ...
Chaotic analog circuits are commonly used to demonstrate the physical existence of chaotic systems and investigate the variety of possible applications. A notable disparity between the analog circuit and the computer model of a chaotic system is usually observed, caused by circuit element imperfectness and numerical errors in discrete simulation. In order to show that the major component of observable error originates from the circuit and to obtain its accurate white-box model, we propose a novel technique for reconstructing ordinary differential equations (ODEs) describing the circuit from data. To perform this task, a special system reconstruction algorithm based on iteratively reweighted least squares and a special synchronization-based technique for comparing model accuracy are developed. We investigate an example of a well-studied Rössler chaotic system. We implement the circuit using two types of operational amplifiers. Then, we reconstruct their ODEs from the recorded data. Finally, we compare original ODEs, SPICE models, and reconstructed equations showing that the reconstructed ODEs have approximately 100 times lower mean synchronization error than the original equations. The proposed identification technique can be applied to an arbitrary nonlinear circuit in order to obtain its accurate empirical model.
... Methods of the second type exploit machine learning or system identification [3][4][5][6][7][8][9][10][11][12]. Using pairs of clean input and distorted output sounds of the target device, the mapping from the input to output is acquired. ...
... Methods of the second type are further classified into two subgroups. Those in the first subgroup are called block-oriented models [3][4][5][6][7]. Electronic circuits in the device typically consist of a linear filtering block followed by a nonlinear clipping block. ...
The present paper proposes a distortion pedal modeling method using the so-called WaveNet. A state-of-the-art method constructs a feedforward network by modifying the original autoregressive WaveNet, and trains it so that a loss function defined by the normalized mean squared error between the high-pass filtered outputs is minimized. This method works well for pedals with low distortion, but not for those with high distortion. To solve this problem, the proposed method exploits the same WaveNet, but a novel loss function, which is defined by a weighted sum of errors in time and time-frequency (T-F) domains. The error in the time domain is defined by the mean squared error without the high-pass filtering, while that in the T-F domain is defined by a divergence between spectral features computed from the short-time Fourier transform. Numerical experiments using a pedal with high distortion, the Ibanez SD9, show that the proposed method is capable of precisely reproducing high-frequency components without attenuation of low-frequency components compared to the state-of-the-art method.
