| 摘要 |
This invention relates to a system for measuring ultrasonically the elastic properties of a moving paper web. An ultrasonic wave generating means (1; 20), generating a noise type ultrasonic signal, creates the ultrasonic wave in the web at an excitation point. A reference ultrasonic receiving means (Mic1, 7; 21, 7) is directed to receive contactlessly the ultrasonic wave from the excitation point. At least two pickup ultrasonic receiving means (Mic2A, 8, Mic2B, 9) receive contactlessly the ultrasonic wave generated by the ultrasonic wave generating means and reradiated by the paper web. A processing means (8 to 10) combines the outputs from the pickup ultrasonic receiving means. A computing means (13) processes the outputs from the reference receiving means and from the processing means, and determines the delay time between these outputs.
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