Signal Processing Using Surface Acoustic Wave Devices and Its Application to Spread Spectrum Communication Systems.
RENSSELAER POLYTECHNIC INST TROY NY MICROWAVE ACOUSTICS LAB
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Three Surface Acoustic Wave SAW devices, the separated-medium convolver, the memory correlator and the chirp filter are analyzed for signal processing applications. Emphasis is placed on convolutioncorrelation and Fourier transformation processes. The chirp filter theory is more general and applied equally well to chirp filters fabricated by alternate techniques. In the SAW convolver there is a piezoelectric delay line. Two surface waves are introduced onto the delay line surface by interdigital transducers at its opposing ends. The two waves overlap beneath a semiconductor spaced above the surface and their fields interact with its charge carriers. A non-linear potential is produced and averaged over the semiconductor. From its back contact is obtained the time-compressed convolution of the two signals. The memory correlator is similar to the convolver except that the semiconductor possesses a charge-storage mechanism. Also additional transducers are required for recovery of stored information. Author
- Non-Radio Communications