Apparatus and method for phase-encoded surface wave devices

An electro-acoustic transducer for providing predetermined frequency characteristics, comprising:

• an acoustic-wave propagating medium;
• a first group of electrically-coupled conducting elements being substantially perpendicular to a first bus bar region connecting all the conducting elements of the first group, said first element group mechanically coupled to said medium;
• a second group of electrically-coupled conducting elements being substantially perpendicular to a second bus bar region connecting all the conducting elements of the second group, said second element group mechanically coupled to said medium, wherein said first group of elements and said second group of elements are interleaved, a plurality of elements of said first and said second group of elements including electrically-coupled element sections, wherein at least one of said coupled sections of the plurality of elements is displaced so as to be in a plane parallel to the element section to which it is electrically-coupled;
• and wherein displacement of said at least one coupled section results in a signal of preestablished amplitude for one of said plurality of elements including said at least one coupled section, and wherein said preestablished amplitude corresponds to a local maxima of a time domain representation for an element of said first group.

An electro-acoustic device for providing predetermined frequency characteristics, comprising:

• an acoustic-wave propagating medium;
• a first transducer coupled to said medium, said first transducer including a first and a second group of electrodes, wherein said first and said second group of electrodes are interleaved;
• a second transducer coupled to said medium for exchanging acoustic-wave signals with said first transducer, said second transducer including a third and a fourth group of electrodes which are substantially perpendicular to a first and second conducting region respectively, wherein said third and said fourth group of electrodes are interleaved, a plurality of said fourth group of electrodes having at least a coupled portion offset in alignment from another coupled portion;
• and
• wherein adjacent electrodes in said first transducer are substantially identical in length, and wherein adjacent electrodes in said second transducer are substantially identical in length.

In a surface wave device of the type including a transducer with interleaved electrodes, an improved method of encoding said surface wave transducer with preestablished frequency characteristics, the interleaved electrodes being substantially perpendicular to a conducting bus bar region, wherein the improvement comprising the steps of:

• a. determining relative locations of transducer electrodes and overlap amplitudes for adjacent transducer electrodes from a time domain representation of said preestablished frequency characteristics;
• b. dividing a plurality of said electrodes into coupled electrode sections;
• c. positioning said coupled electrode sections on a surfacewave propagating material about said determined electrode locations, said coupled electrode sections positioned to provide a combined signal amplitude related to an overlap amplitude for a corresponding electrode section;
• and
• d. positioning undivided electrodes on said surface wave propagating material at said determined locations.

In a surface wave device including transducers with interleaved electrodes which are substantially perpendicular to a conducting bus bar region, an improved method of phase-encoding said surface wave device with preestablishing frequency characteristics, wherein the improvement comprises the steps of:

• a. determining relative location of transducer electrodes and overlap amplitudes for adjacent transducer electrodes from a time domain representation of said preestablished frequency characteristics;
• b. positioning at least a portion of a plurality of said electrodes on a surface-wave propagating material displaced from said electrode relative location, said positioning of said electrodes resulting in a signal determined by said overlap amplitude;
• and
• c. positioning undisplaced electrodes at said determined relative locations.

An electro-acoustic transducer for providing preestablished frequency characteristics;

• comprising
• an acoustic-wave propagating medium;
• a first group of electrodes coupled to said medium and being substantially perpendicular to a first conducting region;
• a second group of electrodes coupled to said medium and being substantially perpendicular to a second conducting region, wherein said second group of electrodes interleaves with said first group of electrodes, a portion of a plurality of electrodes from said first and said second group displaced from positions determined by a time domain representation of said preestablished frequency characteristics.

An electro-acoustic device for providing preestablished frequency characteristics comprising:

• an acoustic-wave propagating medium;
• a first group of electrodes coupled to said medium;
• a second group of electrodes coupled to said medium wherein said first and said second group of electrodes are interleaved;
• a third group of electrodes coupled to said medium and being substantially perpendicular to a first conducting region;
• a fourth group of electrodes coupled to said medium and being substantially perpendicular to a second conducting region, wherein said third and said fourth group of electrodes are interleaved, wherein said third and said fourth group of electrodes are disposed to receive acoustic waves propagated by said first and said second group of electrodes, wherein at least a portion of each of a plurality of electrodes of said third and said fourth group are displaced from preselected positions by predetermined amount whereby the vector addition of signals generated by the third and fourth group of electrodes provide the preestablished frequency characteristics.

An electro-acoustic device having encoding of preestablished frequency characteristic, comprising:

• a first group of electrodes;
• a second group of electrodes, wherein said second group of electrodes is interleaved with said first group of electrodes, said first group of electrodes including a first plurality of sets of portions of electrodes, individual signals generated by each of said sets producing a preselected combined signal;
• said first and second group of electrodes being substantially perpendicular to a first and second conducting region respectively;
• an acoustic-wave propagating medium, said first and said second group of electrodes being coupled to said medium;
• and
• wherein said preselected combined signal is determined by a time-domain representation of said preestablished frequency characteristics.

An electro-acoustic device for providing predetermined frequency characteristics, comprising:

• an acoustic-wave propagating medium;
• a first electro-acoustic transducer mechanically coupled to said medium;
• and
• a second electro-acoustic transducer mechanically coupled to said medium, said second transducer including a multiplicity of interleaved electrodes substantially perpendicular to a conducting region, a plurality of said electrodes having a first portion and a second portion, wherein said first and second portions of electrodes of each group are positioned to produce a composite electrical signal of amplitude and time delay at said first transducer determined by said predetermined frequency characteristics upon electrical excitation of said each group.

An electro-acoustic device for providing predetermined frequency characteristics comprising:

• an acoustic-wave propagating medium;
• an electro-acoustic transducer mechanically coupled to said medium, said transducer including a multiplicity of interleaved electrodes, a plurality of said electrodes having a first portion and a second portion said electrodes arranged to respond to passage of a selected acoustic wave by generating a combined electrical signal of determined amplitude and phase having said predetermined frequency characteristics;
• and
• wherein said combined signal of determined amplitude and phase corresponds to a time domain representation of said predetermined frequency characteristics.