Abstract: A method for locating an identification transmitter of a motor vehicle using a functional device of the motor vehicle involves the identification transmitter transmitting a location signal and the functional device receiving the original location signal and a reflected location signal. The functional device respectively determines a distance to the identification transmitter from the location signals. The functional device checks whether the reflected location signal corresponds to a short-range reflection of the original location signal. Depending on the latter, the functional device locates the identification transmitter.

Abstract: A method for authorizing access to a motor vehicle involves monitoring a decrease in the signal strength of the second communication connection, while the identification transmitter is moved away from the motor vehicle, such that the spacing between the motor vehicle and the identification transmitter increase. The current signal strength of the second communication connection is stored as a reference value as soon as the first communication connection between the motor vehicle and the identification transmitter is deactivated/interrupted. The first communication connection is reactivated as soon as the signal strength of the second communication connection exceeds the stored reference value due to the decreasing spacing between the motor vehicle and identification transmitter when the identification transmitter is moved towards the motor vehicle again.

Abstract: A method for determining the position of a mobile electronic identification device relative to a motor vehicle that can be unlocked by the identification device is provided. In a step a) at least one signal is transmitted from the motor vehicle to the identification device via the first communication connection, the signal containing the transmission time of the at least one signal. In a step b) the transmission time and reception time of the at least one signal received by the identification device is stored in the identification device. In a step c) a data packet is transmitted from the identification device to the motor vehicle via the second communication connection, said data packet containing the stored transmission and reception times of the signals transmitted in step a).

Abstract: A method for operating functional unit of a motor vehicle using an identification system, in which at least a first authorization is requested for operating the functional unit and an identification signal is transmitted to an identification device by an identification element of the identification system. The functional unit is operated after receiving and the functional unit is only operated in a second authorization. The second authorization is generated by the identification device. Using the identification device, a first signal duration of the identification signal is determined for determining a first spacing of the identification element at a first point in time, and a second signal duration of the identification signal is determined for determining a second spacing of the identification element at a second point in time, and the second authorization is generated depending on a comparison.

Abstract: A plurality of keys are registered to the vehicle for opening the vehicle. A respective key must answer within a predetermined timeslot after a first request transmitted by the vehicle, in order to open the vehicle. Several such successive timeslots are provided and several keys are allocated to at least one of these timeslots.

Abstract: A plurality of keys are registered to the vehicle for opening the vehicle. A respective key must answer within a predetermined timeslot after a first request transmitted by the vehicle, in order to open the vehicle. Several such successive timeslots are provided and several keys are allocated to at least one of these timeslots.

Abstract: The invention relates to a method for operating functional unit (32) of a motor vehicle (34) by means of an identification system (36), in which at least a first authorisation is requested for operating the functional unit (32), and in which an identification signal is transmitted to an identification device (38) by means of an identification element (26) of the identification system (36), and the functional unit (32) is operated after receiving, wherein the functional unit (32) is only operated in a second authorisation, and the second authorisation is generated by means of the identification device (38), wherein by means of the identification device (38), a first signal duration of the identification signal is determined for determining a first spacing (A1, A2, A3, A4) of the identification element (26) at a first point in time (t1), and a second signal duration of the identification signal is determined for determining a second spacing (A1?, A2?, A3?, A4?) of the identification element (26) at a second poi

Abstract: A locking system for providing authorization to access and drive a motor vehicle has a first control device for unlocking and locking the car doors, the ignition lock, the steering wheel lock, etc. Additionally, the locking system has a second device, which is an electronic key or an identifier. The two devices have transmission means and/or receiving means for electromagnetic signals with frequencies ? lying in a frequency band between two cut-off frequencies ?a, ?b. At least one of the signals, transmitted between the devices, is a coded operating signal for authenticating the second device. The actual frequency ?i with which the transmission means of the second device is operated is stored in a storage means of the first device.

Abstract: The invention relates to a locking system, for providing authorization to access and drive a motor vehicle. The locking system has a first device, which is a control device for unlocking and locking the car doors, the ignition lock, the steering wheel lock, etc. Additionally, the locking system has a second device, which is an electronic key or an identifier. The two devices have transmission means and/or receiving means for electromagnetic signals with frequencies ? lying in a frequency band between two cut-off frequencies ?a, ?b. At least one of the signals, transmitted between the devices, is a coded operating signal for authenticating the second device. The actual frequency ?i with which the transmission means of the second device is operated is stored in a storage means of the first device.

Abstract: A system for automatic access or driving authorization for a motor vehicle includes a first device in the form of a control device having at least two states for engaging and disengaging vehicle door locks, an immobilizer, or the like. An associated second device is provided in the form of an electronic key, an ID transmitter, a chip card or the like. Both devices have means for transmitting or receiving signals, including a coded operating signal for authenticating the second device, so that a change in the state of the first device can be implemented when the second device is authorized. Before the second device is first activated, it is in a sleep state in which operation-independent function is not permitted and energy consumption is reduced. During a first operator-dependent authentication, the second device is changed over from the sleep state into a standby state in which an operation-independent function is at least partially made possible.

Abstract: A system for automatic access or driving authorization for a motor vehicle includes a first device in the form of a control device having at least two states for engaging and disengaging vehicle door locks, an immobilizer, or the like. An associated second device is provided in the form of an electronic key, an ID transmitter, a chip card or the like. Both devices have means for transmitting or receiving signals, including a coded operating signal for authenticating the second device, so that a change in the state of the first device can be implemented when the second device is authorized. Before the second device is first activated, it is in a sleep state in which operation-independent function is not permitted and energy consumption is reduced. During a first operator-dependent authentication, the second device is changed over from the sleep state into a standby state in which an operation-independent function is at least partially made possible.

Abstract: A portable radio transmitter, especially a remote for a motor vehicle, has a voltage generator for generating an alternating voltage signal, a power-regulatable amplifier stage for amplifying the alternating voltage signal, and a power-regulating circuit with an operational amplifier. One input of the operational amplifier is supplied with a power setting voltage and other input is supplied through a rectifier stage with a feedback voltage signal. A transmitting antenna is supplied by the amplified alternating-voltage signal. The voltage signal generator includes an oscillator and the amplifier stage contains at least one bipolar transistor with its base connected to the oscillator, in whose collector-emitter current path a current adjustment element, controlled by the operational output, is wired. The rectifier stage includes a pair of diodes connected in parallel and in opposite directions and a capacitor and a resistor that are connected in parallel with one of the diodes.

Abstract: A device for triggering an airbag having a controller, a trigger, electric lines between the controlled device and the trigger and a coil for attenuating high-frequency interference currents connected to the electric lines which in turn induces interference current into the lines as a result of an external magnetic alternating field. The attenuation of the induced interference current results from an external magnetic alternating field of the coil and a compensating coil is connected in the electric lines and arranged in the surrounding area of the coil so that the amount of current induced in the compensating coil is equal to that of the interference current induced in the coil by the external field and because they are in anti-phase, the resultant current is zero from any interference.

Abstract: A circuit arrangement for overload protection, particularly for an evaluation electronics unit for child-seat detection in a vehicle, has first and second input connections for an input voltage signal, and first and second output connections for an output voltage signal. The first input connection and the first output connection are connected to one another by means of a first circuit path; and the source/drain path of a first field-effect transistor is included in a second circuit path from the second input connection to the second output connection, to block the second circuit path if an overvoltage is present. The source/drain path of a second field-effect transistor, is included in a third circuit path between the first circuit path and that connection of the first field-effect transistor which is coupled to the second input connection. The second field effect transistor completes the third circuit path when overvoltage is present between the first and the second input connection.

Abstract: An antenna arrangement in a motor vehicle, in particular, an antenna of a radio remotely controllable locking system. The antenna surface is preferably arranged in the region of a window opening of the vehicle, in particular in the windshield, with one surface edge facing a bodywork part. The bodywork part acts as a ground for the RF signals. The antenna arrangement is of simple construction and can advantageously be combined with other functional units.

Abstract: An electronic apparatus for determining the distance between two objects has an interrogation signal generator for generating and transmitting an interrogation signal, and a response signal receiver. An evaluation unit is situated in one object, and interrogation signal reception means and response signal generation means in the other object. According to the invention, the evaluation unit is set up for determining a distance-indicative phase difference between the interrogation signal and the response signal. An electronic security system, such as a vehicle locking system of the keyless-go type, having a distance measurement of this type is also included.