Analog VLSI Processor Implementing the Continuous Wavelet Transform

Abstract

We present an integrated analog processor for real-time wavelet decom(cid:173) position and reconstruction of continuous temporal signals covering the audio frequency range. The processor performs complex harmonic modu(cid:173) lation and Gaussian lowpass filtering in 16 parallel channels, each clocked at a different rate, producing a multiresolution mapping on a logarithmic frequency scale. Our implementation uses mixed-mode analog and dig(cid:173) ital circuits, oversampling techniques, and switched-capacitor filters to achieve a wide linear dynamic range while maintaining compact circuit size and low power consumption. We include experimental results on the processor and characterize its components separately from measurements on a single-channel test chip.