Study on IIR Implementation for Modulation Transfer Function of Room Impulse Response

Abstract

The concept of the modulation transfer function (MTF) is usually used to not only restore the power envelope of reverberant speech but also to predict speech intelligibly in reverberant environments. The generalized room impulse response (RIR) has been proposed to mathematically model real reverberant environments. However, infinite impulse response (IIR) filters of generalized RIRs have not yet been designed from the corresponding MTF and inverse MTF (IMTF) due to the generalized RIR complexity of mathematical derivations. This paper derives the IIR implementation of the MTF and IMTF by using the impulse invariant method and bilinear transformation. Simulations were carried out to evaluate the two types of the derived IIR filters of the MTF and IMTF. It was found that the derived IIR filters with the impulse invariant method are more suitable than those by bilinear transformation.