Research On Precision Ultrasonic Thermometer

The traditional temperature sensor, such as thermoelement whose technology has beenmatured, can only be applied in traditional occasions rather than in many high-tech field.At present many countries is developing new types of temperature sensors pertinently and thespecial and applicable temperature measuring technique. Above all, the ultrasonictemperature sensor is a important temperature measuring technique of them.The principle of the ultrasonic temperature sensor is based on the relationshipbetween temperature and wave velocity in the medium, such as gas, liquid and solid. Thespeed of ultrasonic varies with the temperature in many mediums, such as changing greatlyin high temperature solid or low temperature gas. In this paper the ultrasonic temperaturesensor are designed with the relationship. Putting the sensor in the situation which need tobe measured, we can measure temperature using the relationship of velocity andtemperature when the temperature of the sensor is balanced with environment.Thistemperature sensor consist of ultrasonic transducer, pipe and propagation medium in pipe.Around FPGA in This design, the precision control arithmetic and optimize collectingarithmetic are used to sample the ultrasonic signal. As a result the hardware is built up forthe precision measurement of the ultrasonic propagation time. The design accomplishes theprecision measurement of ultrasonic propagation time according to the related softwarealgorithm based on NIOS_II soft core processor on FPGA chip, and mostly functions andalgorithms are achieved in the chip.