Abstract: A method for estimating the distance between a vehicle and an authentication device, the vehicle including a computer and a plurality of communication modules capable of communicating with the device over a wireless communication link, each communication module including an electronic clock that defines the sampling frequency of the signals received from the device. The method includes in particular the steps of addition of noise to a response signal received from the device, of sampling of the noisy response signal, of detection, at a second instant, of the noisy response signal when the amplitude of the noisy response signal exceeds a predetermined detection threshold, of calculation of the time that has elapsed between a first instant and the second instant, and of estimation of the distance between the vehicle and the device based on the calculated time.

Abstract: A system of at least two units that transmit and/or receive a signal at a first or a second frequency, respectively, each of the units being individually connected to the antenna, which is common to a first branch and to a second branch, respectively. The first branch or the antenna includes first passive electronics preventing passage of the signal at the second frequency to the first unit and allowing passage of the signal at the first frequency to the antenna. The second branch or the antenna includes second passive electronics preventing passage of the signal at the first frequency to the second unit and allowing passage of the signal at the second frequency to the antenna.

Abstract: A method for estimating the distance between an authentication device and a vehicle, in particular a motor vehicle, the vehicle including a computer and a plurality of communication modules capable of communicating with the device by exchanging signals over a wireless communication link, each communication module including an electronic clock that defines the sampling frequency of the signals received from the device. The method includes a plurality of measurement phases each comprising determination, by the computer, of the distance between the vehicle and the device and stopping and restarting of the electronic clock, and estimation of the actual distance between the vehicle and the device based on the plurality of distances determined during the measurement phases.

Abstract: A method for estimating the distance between a vehicle and an authentication device, the vehicle including a computer and a plurality of communication modules capable of communicating with the device over a wireless communication link, each communication module including an electronic clock that defines the sampling frequency of the signals received from the device. The method includes in particular the steps of addition of noise to a response signal received from the device, of sampling of the noisy response signal, of detection, at a second instant, of the noisy response signal when the amplitude of the noisy response signal exceeds a predetermined detection threshold, of calculation of the time that has elapsed between a first instant and the second instant, and of estimation of the distance between the vehicle and the device based on the calculated time.

Abstract: A method for estimating the distance between an authentication device and a vehicle, in particular a motor vehicle, the vehicle including a computer and a plurality of communication modules capable of communicating with the device by exchanging signals over a wireless communication link, each communication module including an electronic clock that defines the sampling frequency of the signals received from the device. The method includes a plurality of measurement phases each comprising determination, by the computer, of the distance between the vehicle and the device and stopping and restarting of the electronic clock, and estimation of the actual distance between the vehicle and the device based on the plurality of distances determined during the measurement phases.

Abstract: A radiofrequency transmission device (D?) includes: a transmission unit (10) for transmitting a voltage signal (S) in pulsed form; a radiofrequency antenna (A); filtering elements (30?); and a voltage source (Vcc), wherein the filtering elements (30?) include: “n” coils (B1, B2. . . Bn), electrically connected in series, of which (n?1) coils each have a natural resonance frequency such that: fRLi=i×fF each having an inductance (Li) such that, at the predetermined fundamental frequency: LTOT=L1+L2+ . . . Li+ . . . Ln=ZTOT=Z1+Z2+ . . . Zi+ . . . Zn and Li=Zi where fRLi Is the natural resonance frequency of the i-th coil i is a number varying from 2 to n, LTOT is the total inductance of the n coils, Li is the inductance of the i-th coil, ZTOT is the total impedance of the n coils, Zi is the impedance of the i-th coil, n is an integer greater than zero.

Abstract: A radiofrequency transmission device (D?) includes: a transmission unit (10) for transmitting a voltage signal (S) in pulsed form; a radiofrequency antenna (A); filtering elements (30?); and a voltage source (Vcc), wherein the filtering elements (30?) include: “n” coils (B1, B2. . . Bn), electrically connected in series, of which (n?1) coils each have a natural resonance frequency such that: fRLi=i×fF each having an inductance (Li) such that, at the predetermined fundamental frequency: LTOT=L1+L2+ . . . Li+ . . . Ln=ZTOT=Z1+Z2+ . . . Zi+ . . . Zn and Li=Zi where fRLi Is the natural resonance frequency of the i-th coil i is a number varying from 2 to n, LTOT is the total inductance of the n coils, Li is the inductance of the i-th coil, ZTOT is the total impedance of the n coils, Zi is the impedance of the i-th coil, n is an integer greater than zero.

Abstract: A radiofrequency transmission device (D?) includes: a transmission unit (10) for transmitting a voltage signal (S) in pulsed form; a radiofrequency antenna (A); filtering elements (30?); and a voltage source (Vcc), wherein the filtering elements (30?) include: “n” coils (B1, B2 . . . Bn), electrically connected in series, of which (n?1) coils each have a natural resonance frequency such that: fRLi=i×fF each having an inductance (Li) such that, at the predetermined fundamental frequency: LTOT=L1+L2+ . . . Li+ . . . Ln=ZTOT=Z1+Z2+ . . . Zi+ . . . Zn and Li=Zi where fRLi Is the natural resonance frequency of the i-th coil i is a number varying from 2 to n, LTOT is the total inductance of the n coils, Li is the inductance of the i-th coil, ZTOT is the total impedance of the n coils, Zi is the impedance of the i-th coil, n is an integer greater than zero.