Analog-digital conversion device with surface elastic waves

An analog-to-digital converter with intermediate frequency conversion, said converter comprising a 4-pole voltage controlled oscillator means and a filter means, both said oscillator means and said filter using an elastic surface wave piezoelectric substrate device wherein the improvement comprises emitter transducer means disposed on said substrate to launch surface waves along a forward track, said filter means being made of reflector means comprised of a network of spaced conductive filaments forming a receiving sub-network overlapping said forward track, a plurality of serially connected transmitting sub-network overlapping a corresponding plurality of backward tracks, the spacing between said conductive filaments of the network series increasing from a transmitting sub-network to the next of the sub-networks, and interconnection portions between said sub-networks, output transducer means overlapping said return tracks, and detector means responsive to said output transducer means for producing a combination of digital signals corresponding to an analog signal applied to a voltage controlled input of said 4-pole oscillator.