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J. Timoney, J. Pekonen, V. Lazzarini, and V. Välimäki, "Dynamic Signal Phase Distortion Using Coefficient-Modulated Allpass Filters," J. Audio Eng. Soc., vol. 62, no. 9, pp. 596-610, (2014 September.). doi: https://doi.org/10.17743/jaes.2014.0033 J. Timoney, J. Pekonen, V. Lazzarini, and V. Välimäki, "Dynamic Signal Phase Distortion Using Coefficient-Modulated Allpass Filters," J. Audio Eng. Soc., vol. 62 Issue 9 pp. 596-610, (2014 September.). doi: https://doi.org/10.17743/jaes.2014.0033
Abstract: When the coefficients of a first-order allpass filter are time modulated by a periodic function, the filter behaves as a dynamic phase distortion device that produces timbral modification of its input. This filter belongs to the class of Periodic Linear Time-Varying (PLTV) systems, and thus it has different properties to the original LTI allpass filter. Such properties include a magnitude response that is not necessarily flat over all time, i.e. not allpass in the usual sense. Many interesting features of these time-varying filters can be discovered by analyzing them in the time and frequency domains. It is important to know too how the time-varying transfer function can be decomposed into recursive and nonrecursive elements, which leads to a criterion for system stability. Additionally, filter topology impacts the output wave shape; only certain configurations produce a low crest factor. These filters offer novel sonic elements for sound designers and the makers of audio effects processors.

@article{timoney2014dynamic,
author={timoney, joseph and pekonen, jussi and lazzarini, victor and välimäki, vesa},
journal={journal of the audio engineering society},
title={dynamic signal phase distortion using coefficient-modulated allpass filters},
year={2014},
volume={62},
number={9},
pages={596-610},
doi={https://doi.org/10.17743/jaes.2014.0033},
month={september},} @article{timoney2014dynamic,
author={timoney, joseph and pekonen, jussi and lazzarini, victor and välimäki, vesa},
journal={journal of the audio engineering society},
title={dynamic signal phase distortion using coefficient-modulated allpass filters},
year={2014},
volume={62},
number={9},
pages={596-610},
doi={https://doi.org/10.17743/jaes.2014.0033},
month={september},
abstract={when the coefficients of a first-order allpass filter are time modulated by a periodic function, the filter behaves as a dynamic phase distortion device that produces timbral modification of its input. this filter belongs to the class of periodic linear time-varying (pltv) systems, and thus it has different properties to the original lti allpass filter. such properties include a magnitude response that is not necessarily flat over all time, i.e. not allpass in the usual sense. many interesting features of these time-varying filters can be discovered by analyzing them in the time and frequency domains. it is important to know too how the time-varying transfer function can be decomposed into recursive and nonrecursive elements, which leads to a criterion for system stability. additionally, filter topology impacts the output wave shape; only certain configurations produce a low crest factor. these filters offer novel sonic elements for sound designers and the makers of audio effects processors.},}

TY - paper
TI - Dynamic Signal Phase Distortion Using Coefficient-Modulated Allpass Filters
SP - 596 EP - 610
AU - Timoney, Joseph
AU - Pekonen, Jussi
AU - Lazzarini, Victor
AU - Välimäki, Vesa
PY - 2014
JO - Journal of the Audio Engineering Society
IS - 9
VO - 62
VL - 62
Y1 - September 2014 TY - paper
TI - Dynamic Signal Phase Distortion Using Coefficient-Modulated Allpass Filters
SP - 596 EP - 610
AU - Timoney, Joseph
AU - Pekonen, Jussi
AU - Lazzarini, Victor
AU - Välimäki, Vesa
PY - 2014
JO - Journal of the Audio Engineering Society
IS - 9
VO - 62
VL - 62
Y1 - September 2014
AB - When the coefficients of a first-order allpass filter are time modulated by a periodic function, the filter behaves as a dynamic phase distortion device that produces timbral modification of its input. This filter belongs to the class of Periodic Linear Time-Varying (PLTV) systems, and thus it has different properties to the original LTI allpass filter. Such properties include a magnitude response that is not necessarily flat over all time, i.e. not allpass in the usual sense. Many interesting features of these time-varying filters can be discovered by analyzing them in the time and frequency domains. It is important to know too how the time-varying transfer function can be decomposed into recursive and nonrecursive elements, which leads to a criterion for system stability. Additionally, filter topology impacts the output wave shape; only certain configurations produce a low crest factor. These filters offer novel sonic elements for sound designers and the makers of audio effects processors.