| 摘要 |
In a method for measuring the vibrations of a test object, an ultrasonic measuring signal having a frequency that is much higher than the vibration frequency of the test object (3) is transmitted from an ultrasonic transmitter (2) towards the vibrating test object. The ultrasonic signal reflected from the test object is detected by an ultrasonic receiver (4) and is frequency-demodulated, and the frequency-demodulated signal is frequency-analysed with a view to determining the vibration frequency and/or the maximum vibration velocity of the test object. Before the vibration measurement, the absence of signals interfering with the ultrasonic signal reflected from the test object is ensured by transmitting from the ultrasonic transmitter (2) an ultrasonic burst signal having the same frequency as the ultrasonic measuring signal. Any signals received by the ultrasonic receiver (4) outside a predetermined time interval for the reception of the ultrasonic burst signal reflected against the test object (3) are essentially eliminated by altering the direction and/or distance of the ultrasonic transmitter and/or the ultrasonic receiver in relation to the test object.
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