| 摘要 |
<p>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.</p> |
