Methods for reducing ringing of ultrasonic transducers

• US 20030039173A1
• Filed: 07/30/2002
• Published: 02/27/2003
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: American Vehicular Sciences LLC (Acacia Research Corporation)
• Original Assignee: Automotive Technologies International Incorporated
• Inventors: Johnson, Wendell C., DuVall, Wilbur E., Yurchenko, Oleksandr V.
• Granted Patent: US 6,731,569 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B06B 1/0215 for generating pulses, e.g. bursts of oscillations, envelopes
• CPC Class Codes: Y10S 367/903 Transmit-receive circuitry

Abstract

Methods for reducing ringing of dual-function ultrasonic air-coupled transducers in which at least one electrical passive circuit is applied to the transducer. The circuit may be either a linear circuit or a non-linear circuit. Different circuits can be applied to the transducer when the transducer is in a transmission mode than when the transducer is in a reception mode.

Claims

1. A method for reducing ringing of dual-function, air-coupled ultrasonic transducers, comprising the step of:

applying at least one inductance in series and/or in parallel to the transducer electrical terminals to obtain a decreased dead zone of the transducer.

2. The method of claim 1, further comprising the step of applying at least one passive electrical circuit in series and/or parallel to the inductance.

3. The method of claim 2, further comprising the step of applying a different electrical passive circuit to the transducer when the transducer is in a transmission mode than when the transducer is in a reception mode.

4. The method of claim 2, wherein the at least one electrical passive circuit is a non-linear circuit.

5. The method of claim 2, wherein the at least one electrical passive circuit is a linear circuit.

6. The method of claim 5, further comprising the step of synthesizing the linear circuit using known input impedance/admittance of the transducer.

7. The method of claim 6, further comprising the step of optimizing the linear circuit on the basis of a broadband matching theory.

8. The method of claim 7, further comprising the step of optimizing the generator output impedance to obtain acceptable ringing at a given input signal.

9. The method of claim 8, further comprising the step of adding non-linear components to the linear circuit.

10. The method of claim 5, further comprising the step of constructing the linear circuit with a higher order transfer function and including at least one capacitor and at least one inductor.

11. An arrangement for reducing ringing of dual-function, air-coupled ultrasonic transducers, comprising:

an electrical passive circuit adapted to be coupled to the transducer, said circuit including at least one inductance adapted to be in series and/or in parallel to the transducer to obtain a decreased dead zone of the transducer.

12. The arrangement of claim 11, further comprising:

an additional electrical passive circuit adapted to be coupled to the transducer; and

switching means for switching between the circuit such that one circuit is coupled to the transducer when the transducer is in a transmission mode and the other circuit is coupled to the transducer when the transducer is in a reception mode.

13. The arrangement of claim 11, wherein said circuit further comprising switching means for modifying said circuit such that a first construction of said circuit is coupled to the transducer when the transducer is in a transmission mode and a second construction of said circuit, different from said first construction, is coupled to the transducer when the transducer is in a reception mode.

14. The arrangement of claim 11, wherein said at least one electrical passive circuit is a non-linear circuit.

15. The arrangement of claim 11, wherein said at least one electrical passive circuit is a linear circuit.

16. The arrangement of claim 15, wherein said linear circuit is synthesized using known input impedance/admittance of the transducer.

17. The arrangement of claim 16, wherein said linear circuit is optimized on the basis of a broadband matching theory.

18. The arrangement of claim 17, wherein the generator output impedance is optimized to obtain acceptable ringing at a given input signal.

19. The arrangement of claim 18, wherein said linear circuit includes non-linear components.

20. The arrangement of claim 15, wherein said linear circuit is constructed with a higher order transfer function and includes at least one capacitor and at least one inductor.

21. A method for reducing ringing of dual-function ultrasonic, air-coupled transducers, comprising the steps of:

providing a plurality of electrical components at least one of which is capable of providing inductance;

coupling a switching device with the components to enable the construction of at least a first circuit and a second circuit depending on the status of the switching device;

selectively coupling the components to the transducer such that the inductance-providing component is in series and/or in parallel with the transducer; and

controlling the switching device in conjunction with the operation of the transducer such that the first circuit is coupled to the transducer during a transmission mode of the transducer and the second circuit is coupled to the transducer during the reception mode of the transducer to obtain a decreased dead zone of the transducer.