Programmable, amplitude and phase, general transversal filter

摘要

A surface acoustic wave (SAW) tapped delay line, including a piezoelectric substrate having a pair of signal launching transducers disposed thereon for providing surface acoustic waves in the substrate in response to electrical signals applied thereto, and including a plurality of transducer taps disposed in an interaction region of the substrate for providing a plurality of sensed electrical signals in response to the surface acoustic waves propagating through the interaction region, the plurality of sensed electrical signals including signals at the frequency of each of the acoustic waves, is combined with a plurality of nonlinear frequency mixers, each responsive to a corresponding one of the transducer taps, and each providing signal manifestations of the sum and different frequencies of the surface acoustic waves in a selected one of two phases which are displaced by 180 DEG with respect to each other, and at signal amplitudes which are selectively adjustable to provide a desired transducer tap amplitude weighting. The selectively adjustable phase and amplitude of the nonlinear frequency mixer signal manifestations provide a programmable SAW delay line suitable for use as a programmable, amplitude and phase, general transversal filter having high programming speed and low power consumption.