A high accuracy continuous wavelet function approximation for implantable device applications

Wavelets as one of the most important signal processing tools are widely used in biosignal research. The continuous wavelet transform based on an analog circuit implementation offers power-efficient real-time signal processing. This paper presents a complexity reduction method of an analog wavelet filter design. The Chebyshev polynomial with higher accuracy approximation is utilized in the wavelet design. In order to simplify the circuit implementation, the transfer function is transformed into the multiplication of biquads. For the proof-of-concept, a Mexican hat wavelet filter circuit is implemented as the multiplication of biquads. The measurement results show that the proposed design process offers higher accuracy approximation and less complex method for the implementation of analog wavelet transform circuit.