Abstract: In a spread-spectrum communication apparatus using a convolver as a correlator, demodulating processes in a receiver apparatus using a carrier and a PN code are performed under a non-synchronous condition.

Abstract: An acoustic surface wave device includes a substrate made of an elastic material, a multilayer structure disposed on a surface of the substrate and having a silicon dioxide layer and an aluminum nitride layer superimposed on each other, and electrodes having predetermined configurations formed on the multilayer structure. The main component of the elastic material is a silicon monocrystal, whose temperature coefficient of delay time for acoustic surface waves is positive, and the piezo-electric axis of the aluminum nitride is either perpendicular or parallel to the surface of the substrate, with a negative delay coefficient, counteracting that of the substrate.

Abstract: A surface acoustic wave device comprises an elastic substrate having a major surface with a given crystal orientation and having a positive temperature coefficient of delay (TCD), and AlN film deposited on the elastic substrate so that piezoelectric axis of the AlN film has a predetermined direction with respect to the major surface of the elastic substrate having a negative TCD, and electrodes provided on the AlN film or between the elastic substrate and the AlN film.