A reprogrammable filter bank using charge-coupled device discrete analog-signal processing

A filter bank having up to 32 channels is formed by multiplexing a recursive two-pole delay line filter. Thirty-two sets of filter constants are stored and addressed digitally while multiple delays are provided in analog form by a charge-coupled device (CCD) delay line. The interface between the digitally stored constant and the delayed analog signal occurs in a four quadrant multiplying D/A where the delayed analog signal is weighted by the constant. Sampling and clamping at the CCD interfaces insures accurate dipolar analog operation. The filter hardware is described, the filter constants are derived, and the performance is documented.