Low voltage programmable current mode circuit for onset detection in a sound signal

This paper proposes a current-mode low voltage CMOS circuit for the detection of onsets in an audio signal. In a reverberant environment, echoes can mask out the original signal at specific time instances. Determining the portions of the received signal which contain a high percentage of the original incident signal is therefore important in a sound localization system. In fact, in the biological localization system, a mechanism exists which masks out echo signals, known as the precedence effect. The circuit described in this paper generates a digital output at instances where the ratio of the received audio signal to the estimated echo signal exceeds a specific threshold. The system has been designed to operate at a supply voltage of 1.8 V, using a standard double-poly double-metal CMOS 0.8 μm technology with a threshold voltage of 0.8 V. To our knowledge, this is the first analogue hardware implementation of such a system