Patent ID: 6865137

Claim:
A method for calibrating an offset interval for received echo pulses in a pulse echo level measurement system, said level measurement system having a transducer for transmitting and receiving echo pulses and including a receiver for converting the received pulses into corresponding pulse profile signals, said method comprising the steps of: (a) transmitting a transmit pulse to a reflective surface; (b) receiving an echo pulse corresponding to the transmit pulse reflected by the reflective surface; (c) converting the echo pulse into a pulse profile signal having a leading edge; (d) defining a first delay interval on the leading edge, said first delay interval corresponding to a time interval between the reception of the echo pulse and the response by the receiver; (e) defining a second delay interval corresponding to a time interval for the leading edge of the pulse profile signal to reach a threshold level; and (f) summing said first delay interval and said second delay interval to determine the offset interval for the echo pulse; wherein said offset interval is subtracted from subsequent measurements of the pulse echo level measurement system so as to provide true measurements.