FPGA active digital cochlea model

Hearing is one of the senses of the human being and and is performed by the auditory system consisting of the outer and middle ear, cochlea (inner ear) and auditory cortex in the brain. The functionality of the cochlea is to process non-linear travelling wave and give information to the brain to perform tasks such as speech recognition and cross correlation of the incoming sound. This paper presents a model of a dual channel human cochlea embedded in a Xilinx XC3S500E, each consisting of a cascade of digital IIR low-pass filters. The filters are based on dual fixed point arithmetic. The model also integrates automatic gain control which mimics the functionality of the outer hair cells (OHCs), as well as the sensing mechanism involved in the inner hair cells (IHCs) of biological cochlea.