Abstract: A system for locking/unlocking at least one motor vehicle openable panel comprising transmission/reception devices which are intended for transmitting, from the vehicle, a radio-frequency interrogation signal, which transmission/reception devices are intended to be carried by a user and which, on receipt of the interrogation signal, are intended for transmitting a radio-frequency identification signal so as to actuate the unlocking of the openable panel, which system comprises detection unit which are linked to the transmission/reception devices on the vehicle and which are able to detect, on an identification signal received on the transmission/reception devices, a modification of a parameter of the transmission, between the transmission/reception means of the vehicle and of the user, which may be due to the interposition, between the vehicle and the user, of intermediate transmission/reception devices.

Abstract: Apparatus for lighting and/or indicating purposes, on a vehicle such as a motor vehicle that has a rear fog lamp. The apparatus includes an electrical supply and a control circuit connecting the electrical supply to the fog lamp and/or an indicator. The control circuit is responsive to activating signals from a fog detector that is adapted to produce the activating signal when a condition of reduced visibility exists in the environment of the vehicle. This activating signal, moreover, is generated in response to electromagnetic waves reflected to a receiver coupled to the fog detector.

Abstract: An electronic circuit, more particularly an harmonic oscillator, is for example arranged as a transmitter for telecontrol signals, especially a remote transmitter for controlling devices such as door locks, anti-theft devices etc. in a motor vehicle. The circuit includes a device for linearising and symmetrizing the response of the amplifier of the harmonic oscillator, which is connected to the output of a means for generating telecontrol words, so as to reduce the output of harmonics.

Abstract: A multi-stage amplifier of low current consumption, such as an onboard receiver for a motor vehicle for receiving telecontrol systems for opening the doors or interrogation signals for the alarm system of the vehicle, has the polarising networks for the amplification stages connected in series in such a way as to reduce the power consumption of the circuitry in the static state. The amplifier stages are connected in series on the polarising bridge in the static state, and in the dynamic state they are connected in cascade. The output of the first stage is connected to the input of the next stage through an impedance matching reactance. In another aspect, gain is controlled by injection/extraction of current between the output terminal of the amplifier and an injection/extraction terminal on the input of the first stage.

Abstract: An electronic device, for example a signal receiver mounted on a vehicle for opening and closing the doors of the vehicle in response to telecontrol signals from a remote source, includes an intermediate frequency amplifier. The intermediate frequency amplifier comprises two amplifier stages arranged in cascade with respect to the input signal, with the biasing terminals of the two stages being connected in series across the supply. The arrangement gives much reduced current consumption.

Abstract: An electronic device comprises, for example, a portable device or a signal receiver mounted on a vehicle for opening and closing the doors of the vehicle in response to telecontrol signals from a remote source. The device comprises two stages arranged in cascade with respect to the input signal, with the polarising terminals of the two stages being connected in series across the supply.

Abstract: A lighting and indicating apparatus for a motor vehicle, for use in poor visibility. The unit includes a fog lamp and apparatus for automatically detecting the presence of poor visibility. The control system for automatic control of the lighting and indicating apparatus includes a humidity detecting circuit and an optical visibility detecting circuit, the outputs from which are combined by a combining circuit, the combined signal then being processed so as to control lighting or extinction of the fog lamp.

Abstract: The circuit comprises:converter means receiving an input train of control pulses and increasing the level of a control signal by a given increment each time it detects a new received pulse, the level of said control signal then decreasing progressively until the following pulse is detected; andthreshold means suitable for producing said wake-up signal when the level of said control signal has reached a predetermined threshold value in such a manner as to produce said wake-up signal only when the number of control pulses applied to the input has reached a predetermined minimum number and providing the recurrence frequency of the pulses is not less than a predetermined limit frequency.

Abstract: A remote control system in particular for locking and unlocking the doors of motor vehicles, the system being of the type including light source forming means associated with optical means adapted to configure the beam generated by the light source, wherein the optical means associated with the light source are adapted to define a transmission lobe centered on an aiming axis and comprising a first component of long range and small beam width together with a second component of shorter range and greater beam width.

Abstract: A remote control system, in particular for locking and unlocking the doors of a motor vehicle, the system being of the type comprising a portable transmitter including means constituting a light source suitable for generating an encoded light flux, and a fixed receiver including photosensitive means designed to receive the light flux and associated with treatment means designed to decode it, wherein the photosensitive means of the receiver comprise a lens having a toroidal aspherical outside surface, which lens is associated with a plurality of photocells.

Abstract: A touch sensor comprises a liquid crystal cell (10) and detector means (40, 50A, 50B) responsive to a change in the dielectric constant of the liquid crystal. The detector means comprise an HF electrical signal generator (40) together with integration means (50A, 50B) suitable for integrating the charge created by any change in the dielectric constant of the liquid crystal (14).

Abstract: In a method and a device for determining the optical transmission factor of a glass panel by identification transmits an incident electromagnetic radiation towards the glass panel and the intensity of the reflected radiation is detected and measured. The reflection coefficient of the panel is compared with reflection coefficient reference values representing the transmission factor of tinted glass reference panels to determine the optical transmission factor of the panel examined.