The information content of demodulated speech

In this paper we describe the effect of demodulation on speech signals. We compare two different algorithms for demodulating audio: the classic approach based on the Hilbert transform and a new approach based on solving a convex optimization problem. We show that convex demodulation better separates the speech information between the modulator and the carrier. We demonstrate this advantage by measuring the speech-information content using a speech-recognition experiment. Finally, we explore the effect of subband filtering on the demodulation process and the shift of information from the modulator to the carrier as the subbands become wider.