Previously, most mammalian auditory systems research has concentrated on human sensory perception whose frequencies are lower than 20 kHz. The implementations almost always used analog vLSI design. Due to the complexi...
Previously, most mammalian auditory systems research has concentrated on human sensory perception whose frequencies are lower than 20 kHz. The implementations almost always used analog vLSI design. Due to the complexity of the model, it is difficult to implement these algorithms using current digital technology. This paper introduces a simplified model of biosonic reception system in bats and its implementation in the ‘‘Chiroptera Inspired Robotic CEphaloid’’ (CIRCE) project. This model consists of bandpass filters, a half‐wave rectifier, low‐pass filters, automatic gain control, and spike generation with thresholds. Due to the real‐time requirements of the system, the system employs Butterworth filters and advanced field programmable gate array (FPGA) architectures to provide a viable solution. The ultrasonic signalprocessing is implemented on a Xilinx FPGA virtex II device in real time. In the system, 12‐bit input echo signals from receivers are sampled at 1 M samples per second for a signal frequency range from 20 to 200 kHz. The system performs a 704‐channel per ear auditory pipeline operating in real time. The output of the system is a coded time series of threshold crossing points. Comparing hardware implementation with fixed‐point software, the system shows significant performance gains with no loss of accuracy.
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