Analog CMOS chipset for 2-D sound localization system

Abstract

2-D sound localization can be carried out by extracting a number of features, known as localization cues, from two received left and right signals. This paper presents the measurement results obtained from three cue extraction chips implemented using standard 0.8 μm double-poly double-metal 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 used for the extraction of spectral cues and time delay cues, respectively. Some test results from each chip are first presented, together with measured cue values. The response of the complete system, with different source locations and under different noise and input signal conditions is then investigated. Results show that 2-D localization accuracy of 5° is possible using hardware-extracted localization cues. The performance of the onset detector in reducing errors arising from echo interference is also assessed. Finally, the localization performance of the system using different sound sources is presented. To our knowledge, these are the first test results obtained from such an analog hardware for a 2-D sound localization system.