Abstract: A method for enabling authenticated access of an individual (10) to a security area (12) by means of a transponder (14) carried by the individual which on receiving an interrogation signal outputs an ID code group, and a control unit (18) located in the security area (12) which generates the interrogation signal and checks the ID code group output by the transponder (14) for enabling access of the individual (10) to the security area (12) only when right of access is authenticated, is characterized in that the interrogation signal is relayed by capactive coupling from the control unit (18) via the individual (10) to the transponder (14).

Abstract: A demodulator 5 is provided which may be constructed at low cost, can be integrated into current systems, and needs no external adjustments. The FSK demodulator 5 comprises a circuit 23 for generating an intermediate signal 101 as a function of high frequency intervals and low frequency intervals of an input FSK signal 100 and a circuit 24 for generating a demodulated output signal 102 as a function of the intermediate signal 101. According to one possible embodiment of the invention, an FSK signal 100 is demodulated by sending an FSK signal 100 through at least two retriggerable monostable multivibrators 23 and 24 each connected to an RC circuit 47 and 48 used to identify the high frequency and low frequency intervals of the input signal. The RC circuit components can be changed to accommodate FSK signals which use different frequencies for high and low input.