Patent ID: 9335194
Filing Date: 2016-05-10
CPC Classification: G01F

Claim Text:
1. System for measuring flow of fluid or gas, comprising: a flow duct, a receiver circuit comprising at least one band pass filter, a microcontroller comprising an analog to digital converter and the microcontroller being connected to said at least one band pass filter, a transmitter circuit, at least two transducers in the flow duct, each of the transducers generating at least one ultrasonic beam in a respective direction in the flow duct and being connected to the transmitter circuit and to the receiver circuit, wherein analog to digital converter arranged to convert an analog signal received by the microcontroller into digital data samples representing at least transit times of the at least one ultrasonic beam generated by each of the at least two transducers and a time difference therebetween, wherein microcontroller is adapted to store the data samples in a memory, wherein the transmitter circuit and the receiver circuit are controlled by a switch that performs continuous switching of the transmitter circuit into a receiver circuit and the receiver circuit into a transmitter circuit, wherein the microcontroller is adapted to stores a vector of data samples for each said respective direction of the of the ultrasonic beams in the flow duct, which vector comprises an appropriate number of N samples forming a frame, the microcontroller being adapted to multiply each frame value with a complex number having fixed magnitude and a phase representing a transmitted frequency corresponding to the transmitted signal in accordance with the following relationship: where X n is the stored value at the n th location, jω is the angular frequency of a transmitted signal, t s representing a sampling time interval and n is the sample number 0≦n<N, wherein the microprocessor is adapted to generate imaginary values and real values, which imaginary values and real values are low pass filtered in a digital filter and sent to an an amplitude function and to a phase detection function, and wherein the microcontroller is adapted to calculate the flow in the duct based on the result of the amplitude function and the result of the phase detection function.