Surface-wave long delay lines

Recent results obtained with helical surface-acoustic-wave (SAW) delay lines of large time delay and bandwidth are described. Both unguided and guided propagation are involved, with time delays up to one millisecond and bandwidths up to 65 MHz being observed. Fiber delay lines of both capillary and cladded types are also discussed. The potential for future application of SAW delay lines of large time-bandwidth product to high-speed signal-and data-processing systems is considered.