Experimental results obtained from analog chips used for extracting sound localization cues

Sound localization, in both azimuth and elevation, using two (left and right) sensors can be carried out by extracting, from the received left and right signals, certain features known as localization cues. This paper presents the test results obtained from three cue extraction chips implemented using standard 0.8 μm CMOS technology (threshold voltage: 0.8 V) and operating at a supply voltage of ±0.9 V. The chips consist of an onset detector which determines those portions of the received waveform which contain primarily incident (as opposed to echo) information, a spectral cue front-end and a time delay estimator. Some block level results are presented, together with measured cue values. To our knowledge, these are the first results obtained from such an analog localization hardware, which has been broadly inspired from the biological auditory system.