04945768 is referenced by 4 patents and cites 5 patents.

A pressure sensor for accurate readings of low pressures utilizes an ultrasonic transmitter which sends a signal to a movable diaphragm via a waveguide. Pressure changes across the diaphragm causes changes in the signal path length from transmitter to receiver which are translated into pressure readings via electronic circuitry employing phase comparator circuitry. The received signal is split into two signals one of which is shifted in phase. A temperature responsive controller selects which received signal is used in a comparison with the transmitted signal thus greatly extending the temperature range over which the sensor operates. The use of an ultrasonic waveguide with a length of at least twice the frequency of the transmitted signal coupled to the transmitter eliminates echoes and reflections and provides for enhanced accuracy in reading even very low pressures.

Title
Pressure sensor
Application Number
7/196562
Publication Number
4945768
Application Date
May 20, 1988
Publication Date
August 7, 1990
Inventor
David F Sorrells
Jacksonville
FL, US
Agent
Arthur G Yeager
Assignee
Parker Electronics
FL, US
IPC
G01L 19/04
G01L 11/00
G01L 7/08
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