Claims
- 1. A method for testing an acoustic device having a plurality of transducing elements adapted for conversion between acoustic and electrical signals, the method comprising:
generating an electrical transmission signal; transmitting the electrical transmission signal to a selected transducing element; receiving an electrical received signal from the acoustic device; generating a reference signal; determining a capacitance associated with the selected transducing element from the reference signal; and diagnosing operational characteristics of the selected transducing element from the determined capacitance and the electrical received signal.
- 2. The method recited in claim 1 wherein the electrical received signal corresponds to an acoustic signal converted from the electrical transmission signal and reflected from a target.
- 3. The method recited in claim 1 wherein the electrical transmission signal comprises a voltage pulse.
- 4. The method recited in claim 1 wherein transmitting the electrical transmission signal comprises routing the electrical transmission signal through a relay element configured for selective routing from a channel to a plurality of channels.
- 5. The method recited in claim 4 wherein transmitting the electrical transmission signal further comprises routing the electrical transmission signal through an adapter having a multichannel switch.
- 6. The method recited in claim 1 wherein the reference signal comprises a linear voltage ramp signal.
- 7. The method recited in claim 1 wherein:
the selected transducing element comprises a piezoelectric crystal; and generating the reference signal comprises generating the reference signal with a frequency less than a resonant frequency of the piezoelectric crystal.
- 8. The method recited in claim 7 wherein generating the reference signal comprises generating the reference signal with a frequency less than 100 kHz.
- 9. The method recited in claim 7 wherein generating the reference signal comprises generating the reference signal with a frequency less than 10 kHz.
- 10. The method recited in claim 7 wherein:
the resonant frequency of the piezoelectric crystal is between 2 and 10 MHz; and generating the reference signal comprises generating the reference signal with a frequency between 0.5 and 1.5 MHz.
- 11. The method recited in claim 1 wherein:
the selected transducing element comprises a cable connection, the capacitance deriving at least in part from a cable capacitance of the cable connection; and diagnosing operational characteristics comprises determining that the capacitance arising from the cable capacitance is a fraction of an expected value.
- 12. The method recited in claim 1 wherein diagnosing the operational characteristics comprises:
determining that an amplitude of the electrical received signal is substantially zero; and determining whether the capacitance is consistent with an expected value.
- 13. The method recited in claim 1 wherein the selected transducing element comprises a plurality of selected transducing elements.
- 14. Apparatus for testing an acoustic device having a plurality of transducing elements adapted for conversion between acoustic and electrical signals, the apparatus comprising:
a transmitter adapted to generate an electrical transmission signal; a relay element adapted to route the electrical transmission signal to a selected transducing element; a receiver adapted to receive an electrical received signal from the acoustic device; and a waveform generator adapted to generate a reference signal with which a capacitance associated with the selected transducing element may be determined.
- 15. The apparatus recited in claim 14 further comprising a computational unit configured to diagnose operational characteristics of the selected transducing element from the determined capacitance and the electrical received signal.
- 16. The apparatus recited in claim 14 wherein the electrical received signal corresponds to an acoustic signal converted from the electrical transmission signal and reflected from a target.
- 17. The apparatus recited in claim 14 wherein the transmitter is adapted to generate the electrical transmission signal in the form of a voltage pulse.
- 18. The apparatus recited in claim 14 further comprising an adapter adapted to interface between the relay element and the transducing elements, the adapter having a multichannel switch.
- 19. The apparatus recited in claim 14 wherein the waveform generator is adapted to generate the reference signal in the form of a linear voltage ramp signal.
- 20. The apparatus recited in claim 14 wherein:
the selected transducing element comprises a piezoelectric crystal; and the waveform generator is adapted to generate the reference signal with a frequency less than a resonant frequency of the piezoelectric crystal.
- 21. The apparatus recited in claim 14 wherein the selected transducing element comprises a plurality of selected transducing elements.
- 22. A computer-readable storage medium having a computer-readable program embodied therein for directing operation of an apparatus including a transmitter, a relay element, a receiver, a waveform generator, and a computational unit, wherein the computer-readable program includes instructions for operating the apparatus to test an acoustic device having a plurality of transducing elements adapted for conversion between acoustic and electrical signals in accordance with the following:
generating with the transmitter an electrical transmission signal; transmitting with the relay element the electrical transmission signal to a selected transducing element; receiving with the receiver an electrical received signal from the acoustic device; generating with the waveform generator a reference signal with which a capacitance associated with the selected transducing element may be determined; and diagnosing with the computational unit operational characteristics of the selected transducing element from the determined capacitance and the electrical received signal.
- 23. The computer-readable storage medium recited in claim 22 wherein the computer-readable program includes instructions for generating the electrical transmission signal in the form of a voltage pulse.
- 24. The computer-readable storage medium recited in claim 22 wherein the apparatus further includes an adapter having a multichannel switch, the computer-readable program further including instructions for transmitting the electrical transmission signal through the adapter.
- 25. The computer-readable storage medium recited in claim 22 wherein the computer-readable program includes instructions for generating the reference signal in the from of a linear voltage ramp signal.
- 26. The computer-readable storage medium recited in claim 22 wherein:
the selected transducing element comprises a cable connection, the capacitance deriving at least in part from a cable capacitance of the cable connection; and the computer-readable program includes instructions for diagnosing operational characteristics by determining that the capacitance arising from the cable capacitance is a fraction of an expected value.
- 27. The computer-readable storage medium recited in claim 22 wherein the computer-readable program includes instructions for diagnosing the operational characteristics by:
determining that an amplitude of the electrical received signal is substantially zero; and determining whether the capacitance is consistent with an expected value.
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is related to the following concurrently filed, commonly assigned U.S. patent applications, the entire disclosure of each of which is incorporated herein by reference in its entirety: “APPARATUS AND METHODS FOR TESTING ACOUSTIC SYSTEMS,” by James M. Gessert et al. (Attorney Docket No. 40100-000200US) and “APPARATUS AND METHODS FOR INTERFACING ACOUSTIC TESTING APPARATUS WITH ACOUSTIC PROBES AND SYSTEMS,” by James M. Gessert et al. (Attorney Docket No. 40100-000300US).