Identification system for verifying an authorization to access an object or to use an object, particularly a motor vehicle

摘要

An identification system is disclosed in which an interrogation signal is emitted on the side of the object, the signal having a carrier frequency which is modified in sections. A mobile encoder (20) encodes the interrogation signal and produces a response signal which is sent back to the object (10). The response signal is mixed with the interrogation signal and decoded in an evaluation unit (14-16) on the side of the object. The distance (d) between the encoder (20) and the object (10) is then determined by means of Fourier transformation (16).