ACOUSTIC SURFACE WAVE TRANSDUCER CONFIGURATION FOR REDUCING TRIPLE TRANSIT SIGNALS

• US 3,810,257 A
• Filed: 02/01/1973
• Issued: 05/07/1974
• Est. Priority Date: 02/01/1973
• Status: Expired due to Term

• Current Assignee: Clinton Sylvester Hartmann, William Stanley Jones
• Original Assignee: Clinton Sylvester Hartmann, William Stanley Jones
• Inventors: Jones, William Stanley, Hartmann, Clinton Sylvester
• Primary Examiner(s): Borchelt, Archie R.
• Assistant Examiner(s): Nussbaum, Marvin
• Application Number:
  US05/328,568
• Time in Patent Office: 460 Days
• Field of Search: 333/3R,72 310/8.1,9.7,9.8
• US Class Current: 333/151
• CPC Class Codes: H03H 9/0285 of triple transit echo
• CPC Class Codes: H03H 9/1455 constituted of N parallel or series transducers

Abstract

An acoustic surface wave transducer configuration characterized by substantial elimination of triple transit reflection output signal related components is provided. The configuration includes two parallel acoustic channels on a suitable substrate. First and second output transducers are defined respectively in the channels, and are off set by one sixth of an acoustic wavelength. The main signal is substantially unaffected whereas triple transit signals are 180* out of phase and electrically cancel.

Claims

1. An acoustic surface wave transducer configuration having a preselected center frequency comprising:

a substrate suitable for propagating an acoustic surface wave;

input transducer means on said substrate for receiving an input signal and generating, responsive thereto, acoustic surface waves in said substrate in first and second substantially parallel acoustic channels; and

first and second output transducers defined respectively in said first and second channels, said first output transducer being spaced from said input transducer means by a first preselected distance and said second output transducer being spaced from said input transducer means by a second preselected distance, the difference between said first and second distances being one-sixth of an acoustic wavelength at said center frequency.

2. An acoustic surface wave transducer configuration as set forth in claim 1 wherein said input transducer means comprises first and second interdigital transducers, said first transducer defining said first acoustic channel and said second transducer defining said second acoustic channel.

3. An acoustic surface wave transducer configuration as set forth in claim 2 wherein said first and second input transducers are electrically connected in series.

4. An acoustic surface wave transducer configuration as set forth in claim 2 wherein said first and second input transducers are electrically connected in parallel.

5. An acoustic surface wave transducer configuration as set forth in claim 1 wherein said substrate defines a groove extending longitudinally between said first and second channels.

6. An acoustic surface wave transducer configuration comprising:

a piezoelectric substrate;

first and second input interdigital transducers having electrode spacings corresponding to a preselected resonant frequency, said input transducers disposed on said substrate to define first and second parallel acoustic channels;

means connected to said input transducers for simultaneously generating acoustic surface waves for propagating in said first and second channels;

a first output interdigital transducer disposed in said first channel for producing a first output signal responsive to an acoustic surface wave propagating therein, said first output transducer laterally spaced a first preselected distance from said first input transducer;

a second output interdigital transducer disposed in said second channel for producing a second output signal responsive to an acoustic surface wave propagating therein, said second output transducer laterally spaced a second preslected distance from said second input transducer, the difference between said first and second preslected distances defining one-sixth of an acoustic wavelength; and

output means connected to said first and second output transducers for providing a resultant output signal which is a combination of said first and second output signals, said resultant output signal being substantially free of components produced responsive to triple transit reflections.

7. An acoustic surface wave transducer configuration as set forth in claim 6 wherein said first and second input transducers are electrically connected in series.

8. An acoustic surface wave transducer configuration as set forth in claim 6 wherein said first and second input transducers are electrically connected in parallel.

9. An acoustic surface wave transducer configuration as set forth in claim 6 wherein said substrate defines a groove extending laterally between said first and second channels.

10. An acoustic surface wave transducer configuration as set forth in claim 6 wherein said output means electrically connect said first and second output transducers in series.

11. An acoustic surface wave transducer configuration as set forth in claim 6 wherein said output means electrically connect said first and second output transducers in parallel.