Reflective delay line as surface wave structure - has spacing of electrode finger(s) in surface wave reflectors differently selected w.r.t. other electrode fingers

摘要

The delay line has an input/output interdigital converter (10) and several surface wave reflectors (11-1 ...), which are fitted at different spacings for realising different transit times of the surface waves between the reflectors and the converter. The distance of at least one electrode finger (12 - 4, N-n) in the surface wave reflectors from an adjacent electrode finger (12 - 3, N-4) is selected in a variable manner w.r.t. the distance of the remaining electrode fingers. Pref. at least one electrode finger has a spacing (B,C), different from an acoustic half-wavelength of the adjacent electrode finger. USE/ADVANTAGE - Converting supplied HF signal into recognition bit code, with improved constant output amplitude of delay line.