| 摘要 |
The checking device uses ultrasonic waves directed onto the banknotes during their transport in a defined direction, provided by a number of transmitters with similar radiation characteristics, operated in phase, for irradiating a defined area of the banknote with a focussed sound field of high intensity. The sound component reflected from the banknote is detected at a relative spacing equal to or less than the sound wavelength and evaluated for determining the thickness or surface weight of the banknote. |
