ANALOG IMPLEMENTATION OF MEDIAN FILTERS FOR REAL-TIME SIGNAL-PROCESSING

A novel median filter using analog tapped delay lines is designed for real-time signal processing. It requires only N+PLU1 analog comparators for a window size of size N. As an extension, a general order-statistics filter can also be realized with moderate increase of circuit complexity. For current available fabrication technology for MOS switched-capacitor circuits, the filter can work at a clock rate up to 10 MHz. This development opens up possibilities for practical applications of nonlinear filtering in real-time signal processing, since the analog circuitry is far less complex than the corresponding digital circuitry.