Abstract: A single high-frequency transmitter emits radiation in a vehicle (1) comprising several seats (2), said high-frequency radiation being reflected depending on whether a seat is occupied, transmitted to a receiver and evaluated with regard to the radiation intensity. In addition, the reliability of the identification is increased, even when the occupant is out of position, by the provision of at least one reflector (9) per seat in or on an allocated seat-belt (6).

Abstract: A single high-frequency transmitter emits radiation in a vehicle (1) comprising several seats (2), said high-frequency radiation being reflected depending on whether a seat is occupied, transmitted to a receiver and evaluated with regard to the radiation intensity. In addition, the reliability of the identification is increased, even when the occupant is out of position, by the provision of at least one reflector (9) per seat in or on an allocated seat-belt (6).

Abstract: A known PASE system is significantly improved by the addition of a LF field, which is restricted to the interior of the motor vehicle, for the purpose of achieving highly reliable differentiation between the inside and outside of the motor vehicle. A LF signal in this field, in the form of a LF ping, is used as a control signal with the function of differentiating between the area inside and outside the motor vehicle and for awakening or activating a semi-active identification transmitter CID. In preferred embodiments, the LF ping itself is preferably not used for data transmission, which continues to be handled in the GHz band, so that the system as a whole also operates very rapidly.

Abstract: A remote control, particularly for wireless remote control of a closing device in a motor vehicle, has a first transmitter for outputting an optical signal, and a second transmitter for outputting a radio signal. The two transmitters are able to be activated for signal output by at least one actuation element. An input of the first transmitter and/or of the second transmitter is connected to a clock transmitter in order to output the optical signal and/or the radio signal in pulsed fashion at particular intervals of time in order to save energy. Also an associated remotely controllable device and a full remote control configuration are disclosed.

Abstract: An antenna system, especially for an anti-theft system of a motor vehicle. A primary magnetic field is produced by a primary coil (2). In the vicinity of the primary coil (2), a coupling coil (11) is disposed which is connected by a flexible conductor (12) with a secondary coil (13). By the magnetic connection of the primary field a secondary field can be produced through the secondary coil (13), which due to the distributed installation of the secondary coils (13) can act specifically in areas in which the primary field is not acting.

Abstract: A remote control, particularly for wireless remote control of a closing device in a motor vehicle, has a first transmitter for outputting an optical signal, and a second transmitter for outputting a radio signal. The two transmitters are able to be activated for signal output by at least one actuation element. An input of the first transmitter and/or of the second transmitter is connected to a clock transmitter in order to output the optical signal and/or the radio signal in pulsed fashion at particular intervals of time in order to save energy. Also an associated remotely controllable device and a full remote control configuration are disclosed.

Abstract: A first challenge signal whose reception power is measured in a portable code transmitter is transmitted by a vehicle-mounted transmission unit. Subsequently, a second challenge signal is transmitted under changed transmission conditions, and the reception power of the second challenge signal is also measured. Doors are unlocked, or the internal combustion engine is started only if the received power levels are also different. Otherwise, one or more challenge signals are transmitted once more under changed transmission conditions.