Recirculating electric and acoustic tapped delay line

Abstract

The recirculating tapped delay line in accordance with the invention is a combination electrical and acoustic recirculation network that includes a selected number of acoustic surface wave circulating subloops included in an electrical primary feedback loop or network with each subloop having a selected number of taps. Each acoustic subloop includes track changing multistrip couplers that inject the signal into the loop, multistrip reflecting track changers at each end of the surface wave path, tapping transducers or multistrip couplers in both forward and reverse acoustic paths and a multistrip loop cancelling switch for suppressing the recirculating signal as desired. Because the recirculation is entirely acoustic in each subloop, the components which contribute substantially to distortion are utilized with less frequency so that the overall distortion after specific storage time is reduced. Also, by repeated recirculation through each subloop, a substantially larger effective number of taps may be realized per actual number of taps during each electrical feedback around the primary overall loop. The combination of primary and subloops in accordance with the invention effectively multiplies the actual number of taps in the subloops by the number of combined acoustic and electrical recirculations, all with a minimum of signal loss and distortion.