Low power switched capacitor implementation of discrete Haar wavelet transform

A low power switched capacitor filter implementation of a Haar discrete wavelet transform is presented. The circuit is to be integrated into the pre-processing unit of an adaptive threshold detection system for environmental protection applications. For a 200Hz sinewave input signal with an amplitude of 200 mV, the simulation results demonstrate a systematic error in computation of wavelet coefficients under ± 1.1 mV with a power consumption of 40 μW. The switched-capacitor circuit is implemented on a 0.5 μm CMOS technology.