Transit-time ultrasonic gas flow meters have gained acceptance in applications for gas transfer distribution. Advantages of this technology include: wide measuring range, relatively high accuracy, good repeatability, negligible pressure drop, general insensitivity to liquid contaminants, insensitivity to fluctuations of the gas composition, and low maintenance.
This application note covers the operating principals of ultrasonic gas flow measurement using the TDC1000 integrated ultrasonic analog-front-end (AFE) device and the TDC7200 precision integrated timer device. It covers additional external circuitry required for boosting transducer drive pulses in gas flow meter application. The benefits of the complementary external circuits are discussed, namely driving the transducer with more energy without the requirement for inductors, and the robust filter and gain stage.