Bang, Click, Thud, or Whack?

coustic transients—short, impulsive bursts of acoustic energy—are a rich source of information in the natural world. Biological systems process them quickly and economically. In this article, we describe a biologically inspired analog very-large-scale integration (VLSI) architecture for real-time classification of acoustic transients. Judicious normalization of time–frequency signals allows an elegant and robust implementation of a correlation algorithm. The algorithm replaces analog–analog multiplication with binary multiplexing of analog signals. This removes the need for analog storage and analog multiplication. Simulations show that the resulting algorithm has the same out-of-sample classification performance (about 93% correct) as a template-matching algorithm based on conventional analog correlation. This development paves the way for intelligent acoustic processing in low-power applications such as cellular telephones and debit cards. (