SIGNAL PROCESSING USING CHARGE COUPLED DEVICES AND SURFACE WAVE DEVICES.

Both Charge Coupled Devices (CCDs) and Surface Wave Devices (SWDs) are distributed delay transversal structures. When contiguously tapped, both can implement an arbitrary bounded impulse response and thus can be used for general signal procesing. CCDs are intrinsically base band devices and SWDs are intrinsically bandpass devices. CCDs have variable propagation delay controlled by an external clock, while SWDs have a fixed propagation velocity determined by elastic constants. The physical properties and applications of both CCDs and SWDs are discussed and compared. Illustrative system applications are examined to show the strengths and weaknesses of both technologies. An electrically alterable CCD filter is discussed and compared with corresponding SWD filters.