| 摘要 |
Method for decreasing the existence of externally detectable revealing signals, so-called RÖS, from keyboards ( 1 ), e.g. for computers, where the keyboard is fed with signals, so-called matrix signals, which are detected for detection of activity regarding the keys ( 2 ) of the keyboard, whereby said matrix signals are generated by means of signal devices. The method is especially characterized in that the matrix signals are high-frequency filtered before they are fed to the keyboard. |
