Electronic component operating with acoustic waves

Claim 1

An electronic component operating with acoustic waves, comprising: a substrate; at least one electromechanical transducer carried on said substrate; at least one finger structure carried on said substrate; at least one of said finger structures comprising at least one region in which fingers are weighted; at least one of said finger weighted structures comprising in said region a plurality of such spaced principal groups extending in a direction Z along the principal axis of wave propagation in said weighted region, each of said principal groups in said region comprising at least two subgroups; said sub-groups extending in said direction Z; each of said sub-groups comprising at least two successive real finger edges and at least an essential number of said sub-groups having an oscillating displacement ΔZ; the number n of all principal groups of the respective finger structure being equal to or greater than T·B, where T·B is the time bandwidth product, with T being the predetermined duration of the predetermined pulse response and B being the predetermined bandwidth of the transfer function of said respective finger structure; the respective amount of displacement ΔZ i of the finger edges of the i th individual sub-group, said i th sub-group belonging to a respective sequence of sub-groups of said weighted region, is determined by an additional oscillating phase modulation b(t) predetermined for said sequence, wherein said phase modulation b(t) being such that the number of oscillation within each individual principal group of said sequence is an integer which is not greater than half the number of sub-groups of said principal group; whereby the relationship e.sup.jb(t) ≈a(t)/r(t) holds true, where e jb (t) is the average of the function e over said individual principal group and approximately equal to a(t)/r(t), where a(t) is the predetermined amplitude modulation of said pulse response, and r(t) is equal to or greater than a(t) for all values of t; and the amount of displacement ΔZ i of the finger edges of a respective i th sub-group at its center Z i is ΔZ.sub.i =(λ.sub.i /2π)·b(t.sub.i), where t i =Z i /v, where Z is the direction of wave propagation with a velocity v and λ i is the local constructive wave length at the location of the i th sub-group.