METHOD OF COMPENSATING ULTRASONIC LEVEL GAUGE MEASUREMENT ERRORS Russian patent published in 2010 - IPC G01F23/28 

FIELD: physics.

SUBSTANCE: time interval between emitted and received ultrasonic pulses is measured and the input analogue signal is converted to a digital code whose frequency is not less than twice greater than frequency of the input signal. After measuring the time interval, the number of extrema in the recorded input signal is determined, from which the lead time of the echo pulse relative the end of the measured time interval is determined from the expression: Δt=T*(N/2) where N is the number of extrema; T is the period of the input analogue signal in µs, and the propagation time of the echo pulse in the controlled medium is determined from the expression: t_p=t₁-Δt=t₁-T*(N/2), where t₁ is the measured time interval in mcs. Distance to the reflecting surface is determined by multiplying the propagation speed of ultrasound in the controlled medium by the measured time interval and this distance is displayed.

EFFECT: compensation of ulstrasonic level gauge measurement errors caused by presence of an uncontrolled time interval between the onset of the echo pulse and triggering of the threshold device.

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