通过对实小波函数的模拟滤波器实现原理进行分析,将其实现过程分解为实小波函数逼近和小波滤波器设计2步,提出一种适合任意实小波函数的高阶开关电流滤波器通用综合方法,并设计具体的电路模型。首先,基于网络系统综合理论,构建实小波函数的通用优化逼近模型;然后,以开关电流双线性积分器和电流镜为基本单元设计出冲激响应为实小波逼近函数的通用多环反馈结构滤波器,通过调节开关电流滤波器的时钟频率获得不同尺度小波函数。以开关电流实Morlet小波滤波器设计为例验证该通用方法的正确性。
A new general synthesis method for high order switched-current filter implementation of arbitrary wavelet function was presented. The method was based on the analytical decomposition of the filter implementation with real wavelet function approximation and wavelet filter design by the analog filter implementation principle of wavelet function. The filter circuit was designed as follows. Firstly, a general optimization approximation model of real wavelet function was structured based on synthesis theory of network systems. Then the general multiple-loop feedback structure filter whose impulse response was the approximated real wavelet function was designed using switched-current bilinear integrators and current mirrors as the basic building blocks. By changing the clock frequency of the filter circuit, the different scale wavelet functions were very precisely obtained. Finally, a switched-current real Morlet wavelet filter was employed to demonstrate the correctness of the realization scheme.