Abstract: The system comprises, on the one hand, a network of radiogoniometers (4.sub.1. . . 4.sub.n) which are coupled to at least one computer and are arranged at well-determined locations of areas of a region, and on the other hand, a set of radio distress beacons (2) which are arranged inside vehicles (1) moving within the areas of the region. The computer (6) comprises means of processing information emitted by the distress beacons and means of connection for locating and identifying in the region the beacons emitting distress signals and for transmitting the corresponding information to the emergency services (9) closest to the places of emission by the beacons.

Abstract: A method and device are provided for the automatic recognition of targets from "Doppler" echoes. The method consists in comparing sequentially the spectra of the "Doppler" signal retransmitted by each target with successions of spectra corresponding to known targets stored in a dictionary memory and indicating the type of target when the spectra of the signal retransmitted by the target have been recognized.

Abstract: The device is of the type comprising a circuit for compressing the dynamic of the speech signal before transmission of the signal at constant level and an expander for re-establishing at reception the speech level before compression thereof. A logic filtering circuit controls the compression circuit by constant attenuation steps depending on the speech level. A selector comparator circuit coupled by a first input to an output of the logic filtering circuit and by a second input to the output of a device controlling the expander compares the attenuation values supplied by the logic filtering circuit with those supplied by the device controlling the expander and adjusts the attenuation value of the compression circuit to the greatest of the attenuation values supplied by the logic filtering circuit or by the control device of the expander.

Abstract: Apparatus for processing speech in radioelectric transmitter/receiver equipment is adapted to transmitting and receiving speech. The apparatus comprises a compression circuit for compressing the dynamic range of the speech signal, said compression circuit being formed by at least one variable transmission attenuator for maintaining the level of speech modulation substantially constant throughout speech transmission. An expander re-establishes on reception the level of speech before it was compressed. An expander control device is responsive to the attenuation value applied by the transmission attenuator and transmitted over an auxiliary radioelectric frequency channel of the equipment. The compression circuit is an incremental compression circuit with a time anticipated action.

Abstract: The interpolation device for the voice coded in DELTA transmission and transmitted on a fixed frequency or with frequency jumps carrier, comprises in parallel on a classic reception network, a jamming detection device being able to be constituted by a high-pass filter in order to detect the components outside the modulated signal band, a detector circuit with threshold fixing the level of the outside band components characterizing a jamming and possibly a monostable circuit. It comprises, furthermore, a rumbling generator that transmits to the input of the DELTA decoder a rumbling sequence in place of the sequence detected on a stage when this sequence is reckoned as jammed by means of a switch controlled by the output of the monostable circuit.

Abstract: An audio squelch circuit uses spectral analysis of the audio signal to derive two test signals, one of the two indicating speech presence "energy" and the other "voiced" speech presence. The two test signals are logic-AND combined to decide speech presence and open the squelch gate. Detection of speech in the audio signal, composed of a voiced segment which is both preceded and followed by a non-voiced (consonant) segment, is improved by correspondingly lengthening the "voiced" test signal pulse with both earlier (anticipatory) initiation by a time interval "D," and with a later (prolonged) completion by a time interval "d".