Programmable phase coded surface wave device

• US 3,961,290 A
• Filed: 02/07/1975
• Issued: 06/01/1976
• Est. Priority Date: 02/07/1975
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Moore, Samuel D.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Nussbaum, Marvin
• Application Number:
  US05/547,900
• Time in Patent Office: 480 Days
• Field of Search: 333/72, 333/30 R, 29/25.35, 235/181, 310/8, 310/8.1, 310/8.2, 310/9.7, 310/9.8, 340/347 AD, 340/347 DA, 340/173.2, 325/32-34, 325/30, 179/1.5 E, 179/1.5 FS
• US Class Current: 333/150
• CPC Class Codes: H03H 9/6406 Filters characterised by a particular frequency characteristic
• CPC Class Codes: H03H 9/6416 SAW matched filters, e.g. surface acoustic wave compressors, chirped or coded surface acoustic wave filters

Abstract

A surface wave device (SWD) programmable to produce any one of a plurality of phase coded SWD digital delay line configurations from a single transducer pattern characterized by parallel transducer electrode arrays to provide for each of two opposite phase alternatives of acoustic surface waves being propagated. Each transducer comprises pairs of interdigital taps, each tap characterizing a single binary bit. Transducer phase coding is accomplished by severing in selected taps all metalized fingers of like polarity from their common conductor bar. Critical configuration tolerances prohibitive to programmed operations are thus obviated.

Claims

1. An acoustic surface wave programmable processor comprising:

substrate means having at least a surface layer of piezoelectric material,

means to produce respective first and second acoustic surface waves of opposite phase wherein the second acoustic surface wave is at least substantially the inverse of the first acoustic surface wave in the piezoelectric material of said substrate means and propagating along two distinct paths,

a first output transducer array having a plurality of sets of electrode elements on the piezoelectric surface of said substrate means and disposed in the first path for sampling the first acoustic surface wave to be propagated therein at spaced time points corresponding to said sets of electrode elements along said first path,

a second output transducer array having a plurality of sets of electrode elements on the piezoelectric surface of said substrate means and disposed in the second path for sampling the second acoustic surface wave to be propagated therein at spaced time points differing from the spaced time points in said first path at which the first acoustic surface wave to be propagated is sampled by said first output transducer array, and

means operably connected to said first and second output transducer arrays for combining respective electrical output signals from sets of electrode elements at successive time points along said first and second paths from said first and second output transducer arrays.

2. An acoustic surface wave programmable processor as set forth in claim 1, wherein said means to produce respective first and second acoustic surface waves comprises a pair of input transducers positioned on the piezoelectric surface of said substrate means in a side by side relationship and having a common input channel to generate said first and second acoustic surface waves along said first and second paths.

3. An acoustic surface wave programmable processor comprising:

substrate means having at least a surface layer of piezoelectric material,

means to produce respective first and second acoustic surface waves of opposite phase wherein the second acoustic surface wave is at least substantially the inverse of the first acoustic surface wave in the piezoelectric material of said substrate means and propagating along two distinct paths,

a first output transducer array having a plurality of sets of electrode elements on the piezoelectric surface of said substrate means and disposed in the first path for sampling the first acoustic surface wave to be propagated therein at spaced time points corresponding to said sets of electrode elements along said first path,

a second output transducer array having a plurality of sets of electrode elements corresponding to like sets of electrode elements of said first output transducer array, said second output transducer array being positioned on the piezoelectric surface of said substrate means and disposed in the second path for simultaneously sampling the second acoustic surface wave to be propagated in said second path at spaced time points in said second path corresponding to said sets of electrode elements of said second output transducer array,

electrode elements of said first and second output transducer arrays being selectively disabled to provide respective electrical output signals from sets of electrode elements at each pair of like time points from only one of said first and second output transducer arrays, and

means operably connected to said first and second output transducer arrays for combining the electrical output signals from said first and second output transducer arrays.

4. A programmable acoustic surface wave device which comprises:

substrate means having at least a surface layer of piezoelectric material,

a plurality of input transducers arranged on the piezoelectric surface of said substrate means in parallel array pairs, each input transducer of each pair being effective to generate an acoustic surface wave opposite in phase and at least substantially the inverse of the acoustic surface wave generated by the other input transducer of each pair, with the acoustic surface waves to be generated by the input transducers of each pair being propagated along two distinct paths, and each input transducer having separated sets of interdigitated fingers,

a plurality of output transducers arranged on the piezoelectric surface of said substrate means in parallel array pairs, each array pair of output transducers having one output transducer in each path of acoustic surface waves to be propagated from a corresponding one of said array pairs of input transducers, with each output transducer of each pair corresponding to a single phase alternative of the acoustic surface waves being propagated opposite in phase to that of the other output transducer and each having sets of separated interdigitated fingers,

input electrode paths interconnecting said plurality of input transducers to provide predetermined acoustic surface waves of phase relationships in said device, and

output electrode paths interconnecting said plurality of output transducers to produce a combined electrical output signal with electrical output signals from sets of interdigitated fingers of each pair of output transducers connected to produce electrical output signals of opposite polarity.

5. A programmable acoustic surface wave device as set forth in claim 4, wherein said sets of separated interdigitated fingers of one output transducer correspond to like sets of separated interdigitated fingers of the other output transducer of each pair, and

selected sets of interdigitated fingers of each of said plurality of output transducers being disabled to effect phase reversals in a coded electrical output signal from said output transducers in response to an electrical signal applied to said input electrode paths.

6. In a phase coded system having a signal receiving circuit, and a signal recognition means, the combination comprising:

substrate means having at least a surface layer of piezoelectric material,

a pair of input transducers on the piezoelectric surface of said substrate means and providing parallel arrays of input transducer electrodes polarized to generate respective first and second acoustic surface waves of opposite phase wherein the second acoustic surface wave is at least substantially the inverse of the first acoustic surface wave, said pair of input transducers being placed in electrical communication with said receiving circuit for accepting input electrical signals therefrom,

a pair of output transducers disposed on the piezoelectric surface of said substrate means and being respectively located in the paths of the first and second acoustic surface waves to be generated by excitation of said input transducers, said pair of output transducers providing parallel arrays of output transducer electrodes arranged in plural separated sets of interdigitated fingers forming plural signal taps along the extents of said pair of output transducers,

sets of said interdigitated fingers of said pair of output transducers from only one of said pair of output transducers at each one of said plural signal taps providing respective electrical output signals from said pair of output transducers, and

means operably connected to said pair of output transducers and to said signal recognition means for combining the electrical output signals produced by said output transducers in response to an electrical signal received by said pair of input transducers from said receiving circuit as a coded signal for input to said signal recognition means.

7. In a phase coded system as set forth in claim 6, wherein said plural signal taps of one of said pair of output transducers correspond to like signal taps of the other output transducer, and

selected sets of said interdigitated fingers of each of said pair of output transducers being disabled in providing respective electrical output signals at each corresponding pair of signal taps from a single signal tap of one of said pair of output transducers.

8. A method of producing phase shift keyed acoustic surface wave devices, which comprises:

forming a pair of input transducers and a corresponding pair of output transducers along two acoustic surface wave propagation paths on a piezoelectric surface of a substrate, wherein the pair of output transducers include corresponding sets of interdigital electrodes forming plural pairs of signal taps, and

disabling a selected one of each of the pairs of signal taps to provide a single operable signal tap of one or the other of said pair of output transducers from each pair of signal taps to effect phase reversals in an electrical output signal obtained from said pair of output transducers corresponding to a sequence of binary code information.

9. A method of producing phase shift keyed acoustic surface wave devices, which comprises:

forming a pair of input transducers on the piezoelectric surface of a substrate having arrays of input transducer electrodes so arranged to generate respective first and second acoustic surface waves of opposite phase wherein the second acoustic surface wave is at least substantially the inverse of the first acoustic surface wave along two acoustic surface wave propagation paths,

forming a pair of output transducers on the piezoelectric surface of the substrate and located in the paths of the first and second acoustic surface waves to be generated by said input transducers, wherein the pair of output transducers includes corresponding plural signal taps of sets of interdigital electrodes, and

disabling a selected one of said signal taps of each pair of corresponding signal taps included in said pair of output transducers so as to provide respective electrical output signals at each corresponding pair of signal taps from only one of said pair of output transducers to effect phase reversals in said electrical output signals corresponding to a sequence of binary code information.

10. A method as set forth in claim 9, wherein the selected signal tap of each pair of signal taps is disabled by severing interdigital electrodes of like polarity from a common conductor bar of one of said pair of output transducers.

11. A method of phase coding a surface wave device comprising:

forming a sequence of electrodes on a piezoelectric surface of a substrate to define a plurality of input transducer bit arrays and a plurality of output transducer bit arrays arranged in parallel, with a first pair of input and output transducer bit arrays corresponding to a single phase alternative signal in propagating and converting a respective acoustic surface wave to an electrical output signal, and a second pair of input and output transducer bit arrays corresponding to a single phase alternative signal in propagating and converting a second acoustic surface wave to an electrical output signal wherein the second acoustic surface wave is at least substantially the inverse of the first acoustic surface wave, and with the output transducer bit arrays provided with respective separated groups of interdigitated electrode fingers forming a plurality of corresponding signal taps.

disabling selected signal taps from said first and second output transducer bit arrays to code the surface wave device, and

combining electrical output signals from said first and second output transducer bit arrays to form a phase-shift-keyed signal.

12. A method of phase coding a surface wave device as set forth in claim 11, wherein selected signal taps are disabled by severing electrode fingers of like polarity from a common conductor bar of one or the other of the first and second output transducer bit arrays.