Abstract: A device for the display of data, comprising on the one hand a matrix of luminous dots (11a, 11b, . . . 11n) each of which is constituted by at least one pair of light-emitting diodes arranged in anti-parallel with the color of the light emitted by one diode of the pair being different from that of the other diode, and comprising on the other hand, an electric a.c. voltage supply source (16) whose output terminals (17 and 18) can be coupled to the supply terminals of the luminous dots by electronic switches (25a, 25b . . . 25m) controlled by a control signal generator (30). A color variation requirement, referred to as "background" of the sign, is obtained by rendering the electronic switches (25a, 25b, . .

Abstract: A receiver in which the detection sensitivity of a detection diode is adjustable as a function of the polarization current, and is controlled by means of a feedback circuit provided with a delay element so that changes in the received signals having a frequency below a value determined by the delay element are eliminated.

Abstract: An anti-interference Doppler effect mini-radar includes a generator of pure microwaves, and a receiver for receiving reflected microwaves and coupled to the generator for detecting and demodulating the transmitted and reflected microwave signals. The demodulated signals are applied to a gain controlled preamplifier, and thence to an adjustable gain amplifier. The output of the adjustable gain amplifier is applied to an alarm control circuit. In order to adjust the gain of the preamplifier a servo-circuit is responsive to the input of the alarm control circuit for applying a gain control voltage to the gain control terminal of the preamplifier. A timing circuit responsive to the output of the adjustable gain amplifier blocks the servo-circuit and inhibits the operation of the alarm control circuit for a determined time following the sudden increase in the output of the adjustable gain amplifier.

Abstract: A Doppler radar device in which a detector diode is arranged in a flared horn which constitutes the aerial of the device. A metal sleeve is arranged in the flared horn perpendicular to the axis and parallel to the smaller sides of the horn, the said body being arranged behind the detector diode (viewed from the radiating side of the horn), and parallel to the diode.