A mask-programmable charge-transfer analog multiplier

A mask-programmable four-quadrant multiplier where an analog multiplication coefficient is stored at each stage of a serial charge-transfer device is described. A serial stream of input data samples d/SUB n/ is multiplied by coefficients c/SUB n/ and sequentially produces an output stream of signal samples c/SUB n/d/SUB n/. Since input and output are both serial and the multiplication coefficients are stored on-chip, the device is ideally suited for performing the pre- and postmultiplication required in a charge-transfer device implementation of the chirp z-transform. Experimental results using this device in conjunction with fixed tap weight transversal filters to perform the chirp z-transform are presented. An architecture for a single-chip spectrum analyzer based on the chirp z algorithm is presented.