| The Wavelet Transform (WT), being called mathematical microscope, has been a new style mathematic analysis method. For the real-time requirements of signal proeessing in projeet, the study of using hardware to realize wavelet transform are developped rapidly. The switched-current technique is a relatively new analog sampled-data signal processing technique that aims to replace Switched-capacitors (SC).The switched-current circuits have conspicuous superiority in the compatibility with standard CMOS process. As a new type of analog circuits, the Switched-current (SI) circuit works at the status of current mode and has the charactics of low voltage and low power.The designing method of the circuits has the charactics of systematization and modularization, so it suits the implementation of the VLSI circuit of the continuous wavelet transform system.The paper analyses the basic principle of wavelet transform, switched-current circuit synthesis theory and the designing method and the realization of continuous using analog circuit. Firstly, the knowledge about the wavelet transform is introduced. The characteristic of time-frequency and multi-resolution about wavelet transform is introduced in detail. The paper has a deep and systemic research on the switched-current as a new technology. The basic units of switched-current are analyzed for emphasis, including delayer module, integrator module and differentiator module etc., especially bilinear differentiator module.This article comprehensively analyzes the main two methods which are the time domain method and the frequency domain method.They are widely used in the realization of continuous wavelet transform. Taylor’s formula is used to unfold continuous wavelet function. The unfolded function can be implemented by Switched-current bilinear differentiator module. Taking the implementation of the DOG wavelet for example, the simulation results indicate the feasibility of the designing method. |
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