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Development of a High Precision Time-Difference Ultrasonic Heat Meter Based on TDC-GP21

The paper introduces a high precision ultrasonic heat meter design based on time-difference method. It analyzes and researches the measure theory of time-difference ultrasonic heat meter, and presents a piecewise interpolation method to calculate the flow. With the low-power chip as the microcontroller, the system adopts high-precision time measurement chip TDC-GP21 for flow measurement as well as the temperature measurement. Compared with traditional heat meter, it is of low power consumption and high measurement precision, and the tests show that the results meet the heat meter industry standard second order accuracy.