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).