Ascertaining reception time of ultrasonic signal - using electroacoustic transducer at receiving point to provide electric signal for regulator comparing evaluating signal with reference

摘要

The ultrasonic signal (3) is converted into a corresp. electric signal by an electro-acoustic transducer (2) at the reception point (4). This signal is conveyed to a signal line (8) via a signal amplifier (7). A regulating circuit (10) is connected to the signal line. The regulating circuit compares the evaluating signal in the signal line with a certain reference level of a reference level signal (p2) and regulates the amplification until the oscillation amplitudes in an oscillating region of the signal on the signal line equals the reference level. During this amplification setting, a threshold switch (13) generates a switching flank (31) to identify the reception time as soon as oscillation half-wave in the oscillating region of the evaluating signals first exceeds a certain switch level, reliably detecting a certain oscillation, of a switch level signal (p3). USE/ADVANTAGE - Measuring parameters, qualities or conditions of gaseous liq., or solid medium by ultrasonic signals. Accurate detection of reception time of returned signals.