Switched Capacitor Wavelet Filter for VLSI Implementation

由于小波变换的伸缩性，在民用和军用环境中，小波变换都是处理宽带信号的首选方法。不幸的是，它的计算需要大量的数值运算。在许多情况下，这可能是令人望而却步的昂贵并非不切实际。包括光学方法在内的模拟并行处理技术不适合于实际应用，或者不够精确，因此对于商业化是可能的。开关电容技术用高速开关和电容器的适当组合来代替电阻，在有源滤波器设计的VLSI实现中没有使用。开关电容电路最重要的特性是其时钟频率控制滤波器参数。该方案的目的是用开关电容电路实现小波变换。造成这种可能性的原因是观察到小波滤波器中的膨胀效应可以通过调整时钟频率来实现。利用现有的基于该方案的VLSI技术，可以在一片芯片上实现大量的小波滤波通道。这些IC芯片可以用作具有更高分辨率的信号处理单元中的标准组件。它们还将提供可靠的实时处理，并与其他最先进的电子设备完全兼容。这些设备有望在不久的将来实现商业化。

Because of its dilation property, the wavelet transform is the preferred approach for processing broadband signals in both civil and military environments. Unfortunately, its computation requires a large number of numerical operations. In many situations, this may be prohibitively expensive is not unrealistic. Analog parallel processing techniques including optical methods are either unsuitable or not accurate enough for practical applications, and hence, for possible commercialization. Switched-capacitor techniques, which substitute appropriate combinations of high- speed switches and capacitors for resistors, are not used in VLSI implementations of active filter designs. The most important property of a switched-capacitor circuit is that its clock frequency controls the filter parameters. The purpose of this proposal is to implement the wavelet transform using switched-capacitor circuits. What makes this possibility is the observation that the dilation effect in a wavelet filter can be realized by the adjusting of the clock frequency. By using current VLSI techniques based on the proposed scheme, large numbers of wavelet filter channels can be fabricated on a single chip. These IC chips can be used as standard components in a signal processing unit having increased resolution. They will also offer reliable real-time processing and full compatibility with other state-of-the-art electronic equipment. Near future commercialization of these devices is anticipated.