Implementation Of Continuous Wavelet Transform Based On Switehed-current Circuit

Wavelet transform is the Fourier analysis developed on the basis of a new subjectin the late1980s, due to continuous wavelet transform in the time domain andfrequency domain all have good local characteristics in signal analysis, especiallysuitable for the edges measurement, fractal, signal processing for unsteady signalanalysis. But, plenty of calculation of wavelet transform by a computer which oftenwith computer to complete the time-consuming, hard for real-time processing. So thehardware realization of the continuous wavelet transform have been concerned deeply.Switch current circuit which has obvious advantages to achieve continuous wavelettransform: compared with simple circuit switched capacitor circuit, switch currenttechnology which need not linear float capacitance or operational amplifers adoptdigital CMOS technology of current simulation sampling data processing technology,and does not exist of operational amplifier non-ideal characteristics, the restrictionand error brought more suitable for CMOS VLSI technology, convenient for circuitintegration of low-pressure and low power consumption.This paper introduces the basic theories of wavelet transform knowledge,elabo-rate continuous wavelet transform, binary wavelet transform and discrete wavelettransform. To switch Current technology in-depth research and analysis, probes intothe basic modules of switch current circuit, especially double second quarter filter ofswitch current integrator.Fininally, several achieve continuous wavelet transform hasbeen introduced is analog or mixed-signal circuit.This paper analyzes and summarizes the implementations of continuous wavelettransform based on switehed-current circuit.The paper take Marr wavelet as aexample,and then proposed with Legendre-Padé method to approximate Marr wavelet.That is to say the rational fraction of Marr wavelet function can be given by Padéapproximation of which the classic function order {x~i： i=1，2,3∧} is replaced byLegendre function.The precision of Legendre-Padé approximation is better thanclassic Padé approximation by MATLAB simulation. Band-pass filter of Marr waveletusing cascade form of four pairs of biquadratic section filter is realized.At the end ofthis paper simulate the circuit by switch current circuit special software,andemplement Marr wavelet function.The oretical analysis and simulation resultsindicated a good performance of wavelet transform.