Siemens Aktiengesellschaft

Thomas Reisinger

Robert Fischer

A method for receiving first signals and further signals using a receiver, the first and further signals differing in at least one of the transmission parameters data rate, modulation type, wake-up criterion, synchronization and threshold value, comprises the steps of: in a first step, in a quiescent mode of the receiver, receiving and searching for a wake-up criterion (A) is performed intermittently using a first preset adjustable configuration of transmission parameters, and when no signal is received and no wake-up criterion (A) is found, the system switches to at least one further configuration and a search is made for a wake-up criterion (B).

Receiver and method for scanning and receiving wake-up signals with multiple configurations

The invention relates to a method and apparatus for protecting a transmission path between a base unit and a mobile key unit in an access control system, in particular for motor vehicles. A carrier signal which is modulated with a user signal is transmitted from a transmitting unit to a receiving unit. According to the invention, a separate reference signal, which has a fixed phase angle with respect to the carrier signal, is also transmitted. The phases of the reference signal and of the carrier signal are compared in a test circuit, and an alarm signal is emitted if a phase difference which varies with time is found.

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Wuppertal, Germany

Thomas Reisinger