Acoustic transmission

• US 9,106,322 B2
• Filed: 09/06/2010
• Issued: 08/11/2015
• Est. Priority Date: 09/04/2009
• Status: Expired due to Fees

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Bagshaw, John Martin, Kent, Lionel William John
• Primary Examiner(s): HULKA, JAMES R
• Application Number:
  US13/392,361
• Publication Number:
  US 20120155221A1
• Time in Patent Office: 1,800 Days
• Field of Search: 367/131, 367/137
• US Class Current: 1/1
• CPC Class Codes: G01S 15/96 for locating fish
• CPC Class Codes: H04B 11/00 Transmission systems employing sonic, ultrasonic or infrasonic waves

Abstract

In apparatus for the acoustic transmission of power or data through a solid barrier such as a ships hull, assembly of an acoustic transducer to the hull is facilitated by bonding it first to an intermediate element by a thin layer of bonding adhesive and then bonding the intermediate element to the barrier using a second bonding layer. Acoustic matching of the transducer to the intermediate element is achieved by the thin layer, and the mechanically more robust base of the intermediate element can be rubbed on the barrier surface to displace or abrade away any unwanted debris or imperfections which might otherwise prevent the achievement of a thin second bonding layer. This makes the mounting and bonding process more tolerant of imperfections in the barrier surface due to either surface defects or particulate contamination. The transmit and receive transducers may be positioned relative to each other so as to suppress or attenuate multiple-transit signals. Thus the intermediate element may be wedge shaped to aid suppression of triple-transit signals. Transmit and receive transducers may have different wedge angles.

Claims

1. An apparatus for the transmission of data-bearing acoustic signals through a solid rigid substrate, the apparatus comprising:

a first acoustic transducer for converting data-bearing electrical signals into data-bearing acoustic signals, the first transducer being mounted on a first face of a solid rigid substrate to transmit the acoustic signals into the substrate, the first transducer comprising an upper electrode and a lower ground plane electrode, the first transducer being mounted via a first intermediate element disposed between the first transducer and the first face of the substrate; and

a second acoustic transducer mounted on a second face of the substrate so as to receive the acoustic signals emitted by the first transducer and to convert the acoustic signals into data-bearing electrical signals, the second transducer comprising an upper electrode and a lower ground plane electrode, the second transducer being mounted via a second intermediate element disposed between the second transducer and the second face of the substrate;

wherein the intermediate elements are shaped such that the first and second transducers are positioned relative to each other and/or to the substrate such that multiple-transit acoustic signals propagating between said first and second transducers are directed away from the second transducer and/or are attenuated by interference, and thereby suppressed.

2. The apparatus of claim 1 wherein the first and second transducers have boresights which are laterally spaced from each other.

3. The apparatus of claim 2 wherein the first and second transducers have boresights disposed substantially parallel to each other.

4. The apparatus of claim 1 wherein the first and second transducers have boresights which are not parallel to each other.

5. The apparatus of claim 1, wherein:

the first intermediate element is shaped to suppress resonant acoustic reflections between the first transducer and the first face of the substrate;

the second intermediate element is shaped to suppress resonant acoustic reflections between the second transducer and the second face of the substrate; and

boresights of the first and second transducers are inclined to each other at an angle such that a said multiple-transit signal incident on the second transducer has a phase variation across the second transducer such that electrical signals induced in the second transducer by said signal are attenuated by mutual interference.

6. The apparatus of claim 1 wherein at least one of the first and second intermediate elements is wedge-shaped.

7. The apparatus of claim 1 wherein each of the first and second intermediate elements is wedge-shaped.

8. The apparatus of claim 1 wherein the substrate is part of a metal structure.

9. The apparatus of claim 1 wherein the substrate is part of a hull of a submarine or other vessel, or of a armored fighting vehicle or of a pressure vessel.

10. An apparatus for the transmission of data-bearing acoustic signals through a solid rigid substrate, the apparatus comprising:

a first acoustic transducer for converting data-bearing electrical signals into data-bearing acoustic signals, the first transducer comprising an upper electrode and a lower ground plane electrode, the first transducer being mounted on a first face of a solid rigid substrate to transmit the acoustic signals into the substrate; and

a second acoustic transducer comprising an upper electrode and a lower ground plane electrode, the second transducer being mounted on a second face of the substrate so as to receive the acoustic signals emitted by the first transducer and to convert the acoustic signals into data-bearing electrical signals;

wherein each of the first and second transducers comprises a wedge-shaped intermediate element disposed between a said transducer and the face of the substrate on which it is mounted such that the first and second transducers are positioned relative to each other and/or to the substrate such that multiple-transit acoustic signals propagating between said first and second transducers are directed away from the second transducer and/or are attenuated by interference, and thereby suppressed.

11. An apparatus for the transmission of data-bearing acoustic signals through a solid rigid substrate, the apparatus comprising:

a single pair of transducers, comprising;

a first acoustic transducer for converting data-bearing electrical signals into data-bearing acoustic signals, the first transducer being mounted on a first face of a solid rigid substrate to transmit the acoustic signals into the substrate, the first transducer comprising an upper electrode and a lower ground plane electrode, the first transducer being mounted via a first intermediate element disposed between the first transducer and the first face of the substrate; and

a second acoustic transducer mounted on a second face of the substrate so as to receive the acoustic signals emitted by the first transducer and to convert the acoustic signals into data-bearing electrical signals, the second transducer comprising an upper electrode and a lower ground plane electrode, the second transducer being mounted via a second intermediate element disposed between the second transducer and the second face of the substrate;

wherein the intermediate elements are shaped such that the first and second transducers are positioned relative to each other and/or to the substrate such that multiple-transit acoustic signals propagating between said first and second transducers are directed away from the second transducer and/or are attenuated by interference, and thereby suppressed.