US Patent 10088348 Ultrasonic gas flow meter based on FPGA and DSP

An ultrasonic gas flow meter based on FPGA and DSP consists of ultrasonic gas transducers and sensor components, transmitting/receiving signal channel switch circuits, a driving signal generation and amplification circuit, an echo signal conditioning and collection circuit, a time sequential controlling and signal processing circuit, a man-machine interface, a serial communication module and a power management module, propagation time of ultrasonic echo waves is calculated by adopting a variable ratio threshold and zero-crossing detection method of tracking maximum peak of the echo signal to obtain gas flow rates.