Method of exciting a piezoelectric crystal
First Claim
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1. A method of exciting a piezoelectrical crystal in an ultrasonic ranging device that generates an ultrasonic signal and receives an echo of the ultrasonic signal to determine a fuel level, comprising:
- generating a drive voltage;
placing opposing sides of the piezoelectrical crystal in electrical communication with the drive voltage;
applying a first pulse of substantially the same voltage as the drive voltage to a first opposing side and simultaneously applying zero voltage to a second opposing side; and
applying a second pulse of substantially the same voltage as the drive voltage and substantially the same duration as the first pulse to the second opposing side and simultaneously applying zero voltage to the first opposing side to thereby alternatively pulse the opposing sides.
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Abstract
The invention describes the use of an electrical pulse that is a single square wave to excite a piezoelectric crystal. This pulse is applied alternately to either side of the crystal at twice the nominal resonant frequency of the crystal. This method provides a significant increase in net drive power to the crystal without the need to provide a sine wave excitation of plus and minus voltage to the crystal.
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Citations
20 Claims
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1. A method of exciting a piezoelectrical crystal in an ultrasonic ranging device that generates an ultrasonic signal and receives an echo of the ultrasonic signal to determine a fuel level, comprising:
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generating a drive voltage; placing opposing sides of the piezoelectrical crystal in electrical communication with the drive voltage; applying a first pulse of substantially the same voltage as the drive voltage to a first opposing side and simultaneously applying zero voltage to a second opposing side; and applying a second pulse of substantially the same voltage as the drive voltage and substantially the same duration as the first pulse to the second opposing side and simultaneously applying zero voltage to the first opposing side to thereby alternatively pulse the opposing sides. - View Dependent Claims (2, 3, 4)
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5. A method of exciting a piezoelectrical crystal in an ultrasonic ranging device that generates an ultrasonic signal and receives an echo of the ultrasonic signal to determine a fuel level, comprising:
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generating a drive voltage; placing opposing sides of the piezoelectrical crystal in electrical communication with the drive voltage; applying a first series of pulses of substantially the same voltage as the drive voltage to a first opposing side and simultaneously applying zero voltage to a second opposing side; and applying a second series of pulses of substantially the same voltage as the drive voltage to the second opposing side and simultaneously applying zero voltage to the first opposing side, wherein the second series of pulses alternates with the first series of pulses. - View Dependent Claims (6, 7, 8, 9)
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10. An ultrasonic ranging device to generate an ultrasonic signal and receive an echo of the ultrasonic signal to determine a fuel level, comprising:
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a drive circuit to generate a drive voltage; a switch in electrical communication with the drive circuit to receive the drive voltage; a piezoelectric crystal having first and second opposing sides in electrical communication with the switch; and wherein the switch is configured to apply a first pulse of substantially the same voltage as the drive voltage to the first opposing side and simultaneously applying zero voltage to a second opposing side, and configured to apply a second pulse of substantially the same voltage as the drive voltage and substantially the same duration as the first pulse to the second opposing side and simultaneously apply zero voltage to the first opposing side to thereby alternatively pulse the opposing sides. - View Dependent Claims (11, 12, 13, 14)
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15. An ultrasonic ranging device to generate an ultrasonic signal and receive an echo of the ultrasonic signal to determine a fuel level, comprising:
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a drive circuit to generate a drive voltage; a switch in electrical communication with the drive circuit to receive the drive voltage; a piezoelectric crystal having first and second opposing sides in electrical communication with the switch; and wherein the switch is configured to apply a first series of pulses of substantially the same voltage as the drive voltage to the first opposing side and simultaneously apply zero voltage to a second opposing side, and to apply a second series of pulses of substantially the same voltage as the drive voltage to the second opposing side and simultaneously apply zero voltage to the first opposing side, wherein the second series of pulses alternates with the first series of pulses. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification