Electronic apparatus e.g. mobile telephone, reactivating device for switching apparatus from standby mode to active mode, has sensor supplying electric signal, and bandwidth filter with single capacitor receiving electric signal

摘要

The device has a sensor (12) for supplying an electric signal of a variable level corresponding to swiping of ridges and valleys of a fingerprint in front of the sensor. A bandwidth filter (FB) with a single capacitor receives the electric signal and provides a filtered signal with reduced variations outside a determined frequency band. An output of an average value detector (RD) is applied to a threshold detector (DTH) to provide an active mode control signal for reactivating the apparatus only if the filtered signal has exceeded a preset threshold during a preset minimum period of time. An independent claim is also included for a process for reactivating an electronic device having an active mode and a standby mode.