Synthesis of SAW-correlator with integrated spectrum-shaping
P.G. Schelbert · 2003
A synthesis procedure for SAW (surface acoustic wave) correlators that minimizes the undesired time sidelobes and allows simultaneous spectrum shaping has been developed. The design is based on binary-phase-shift-keying (BPSK)-modulated pseudorandom digital codes, which usually are used for direct sequence spread spectrum. To design the structure of the IDTs (interdigital transducers), a straightforward deconvolution technique is used. A 70-MHz correlator with the 13-b Barker code and a 100-MHz correlator with a 103-b code have been tested. The 70-MHz correlator achieved a time sidelobe ratio of 31 dB and the 100-MHz correlator a ratio of 29.9 dB. These correlators have been developed for a real-time multipath measuring system for mobile radio.>