Uppsala universitet

Causal IIR Audio Precompensator Filters Subject to Quadratic Constraints.

Simon Widmark

IEEE Transactions on Audio, Speech and Language Processing , vol. 26, No. 10, October 2018, pp. 1897-1912.
© 2018 IEEE (Open Access)

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Infinite impulse response (IIR) Wiener precompensator design, with constraints on causality, is here extended to also incorporate general quadratic constraints.

A method for finding a linear quadratic (LQ) optimal, causal discrete-time Multiple-input multiple-output (MIMO) filter subject to a set of user defined constraints is proposed and analysed.

A method for designing causal filters subject to constraints on the power gains in a large number of small frequency intervals is also proposed.

The resulting set of methods provide constrained stable IIR filters with optimal parametrization. Compared to finite impulse response (FIR) Wiener filtering, the computational complexity is much lower and compared to non-causal frequency domain designs, we gain control of the time-domain properties of the compensated system.

The design methods are applied to a room compensation audio problem subject to filter power gain constraint(s) and are compared to a corresponding non-causal per-frequency method. The results are presented with audio filtering and sound field control as main motivating applications but the methods extend to other areas of linear feed forward controller design and Wiener filtering.

Related publications:
PhD Thesis 2018 by Simon Widmark.

Paper applying the presented methodology on causal MSE-optimal filters for personal audio subject to constrained contrast.

AES Munich 2012 Acoustical Zone Reproduction for Car Interiors Using a MIMO Framework.

IEEE ACC 2012 on MIMO design of active noise controllers for car interiors.

IEEE TASLP 2014 on the design and analysis of LQG feedforward controllers for active noise control.

| Reseach on audio signal processing | Main entry in list of publications |
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