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Browse Prior Art Database

Temperature Compensation of Ultrasonic Transducers

IP.com Disclosure Number: IPCOM000095787D
Original Publication Date: 1964-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Dinan, RF: AUTHOR

Abstract

Ceramic transducers of the type employed in ultrasonic document sensing systems have an inherent drift from resonant frequency due to temperature changes. If the oscillator supplying power to the transmitting transducer is stable, a mismatch results with accompanying loss of power.

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Temperature Compensation of Ultrasonic Transducers

Ceramic transducers of the type employed in ultrasonic document sensing systems have an inherent drift from resonant frequency due to temperature changes. If the oscillator supplying power to the transmitting transducer is stable, a mismatch results with accompanying loss of power.

In order to compensate for such frequency versus temperature changes, the system is arranged so that the oscillator frequency controlling element, such as a crystal, for example, is physically located in the same vicinity as the transmitting and receiving transducers. Thus, the crystal will be affected to the same degree by temperature changes.

Accordingly, even if the response characteristics of the transmitters and receivers change, the oscillator frequency controlling element also has an accompanying change. This, in turn, causes the frequency to change by a sufficient amount to cause the system to remain matched for a maximum power transfer.

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