Low voltage log domain front end for the extraction of 2-D sound localization cues

This paper proposes a novel current-mode front end for the extraction of localization spectral cues from two audio signals. A current mode log domain implementation via subthreshold MOS operation is used for micropower operation while still achieving a good bandwidth. In addition, log domain processing results in good linearity. A current mode solution is also preferred because of the ease of implementation of certain mathematical operations. The front end splits the input signals into different frequency bands and computes monaural and interaural spectral cues from the resulting signal envelopes for each band. The front end has been optimized to operate at a supply voltage of 1.8 V and most blocks have been designed using a differential architecture. To our knowledge, this is the first log domain implementation of a front end with localization cues extraction. The design has been carried out using a standard double-poly double metal 0.8 μm CMOS process with V_T = 0.8 V