Abstract: The device forms first and second signals by mixing the input radio signal with two respective quadrature waves of frequency f.sub.O. An algebraic sum of these two signals is phase-shifted by .+-.45.degree. or .+-.135.degree. at an intermediate frequency f.sub.I. An output signal is formed by an algebraic sum between the phase-shifted signal and the first or second signal, in such a way that, at the intermediate frequency f.sub.I, the output signal has a phase representative of that possessed by the input radio signal at a communication frequency f.sub.C of the form f.sub.O -f.sub.I or f.sub.O +f.sub.I, with rejection of the phase of the input radio signal at the image frequency 2f.sub.O -f.sub.C.

Abstract: A linear prediction analysis is performed for each frame of a speech signal to determine the coefficients of a short-Term synthesis filter. For each sub-frame, an excitations sequence which, when applied to the short-term synthesis filter generates a synthetic signal representative of the speech signal, is determined by means of an iterative process in which a symmetrical matrix B.sub.n, is gradually built up with each iteration. The matrix B.sub.n is reversed with each iteration by decomposing the pattern B.sub.n =L.sub.n .multidot.R.sub.n.sup.T with L.sub.n =R.sub.n .multidot.K.sub.n where L.sub.n and R.sub.n are triangular matrices and K.sub.n is a diagonal matrix, and matrix L.sub.n has only 1s on its main diagonal.

Abstract: On the moving body, the apparatus comprises an active transponder, and on the track it comprises a passive responder. The transponder has an LF transmitter and an MF transmitter which, during displacement of the moving body, transmit to a zone through which the responder passes during said displacement. The responder has an LF receiver circuit and an MF receiver circuit having tuned radiating circuits that are associated so that an LF signal induced in the LF circuit causes the MF radiating circuit of the responder to be closed at the LF rate. The transponder responds to disturbances in the MF transmitter caused by the MF circuit of the responder being closed. The MF circuit of the responder includes two units having respective tuned radiating circuits that are strongly coupled together. Each is connected to a respective logic unit which, when excited, delivers a digital message causing the MF radiating circuit to be closed only for bits of a determined value in the digital message.

Abstract: The echo canceller is designed to be placed between a hands-free acoustical interface and a communications network. It comprises a plurality of processing paths connected in parallel and each allocated to one of a plurality of adjacent sub-bands taken from the spectrum band of the output signal. Each path comprises an analysis filter receiving the echo-containing signal for transmission after correction, a second analysis filter receiving the incoming signal coming from the network, and feeding an adaptive filter that supplies an estimated echo in the respective sub-band to the subtractive input of the subtracter and a synthesis filter. The adaptive filters in at least some of the sub-bands implement a QR decomposition RLS algorithm on the incoming signal, using the fast version thereof, with or without recursive order.

Abstract: A device for interfacing from the LLL level to the TTL and CMOS level that comprises, in cascade, a first and a second amplifier-inverter and a shaping circuit delivering an inverted logic signal at the TTL level. A power inverter-amplifier circuit receives the inverted logic signal at the TTL level and delivers an amplified logic signal at the TTL level.

Abstract: A servomechanism is controlled to move at a rate below a critical limit by means of a feedback controller (10) which is responsive to the output of a rate measurement device (9). The feedback controller (10) has a non-linear response whose effect only becomes appreciable when the measured rates approach the critical limit. Operation within the critical limits ensures stable and accurate operation of the servomechanism.

Abstract: Based on the sequence of the information bits to be transmitted, the coder forms a second sequence of bits c.sub.n, which includes a redundant subset. A differential coding of the form d.sub.n =c.sub.n .sym.d.sub.f(n) with f(n)<n produces a third sequence of bits d.sub.n. The signal sent represents the bits of the third sequence in a specified order. Having obtained likelihood data r.sub.n associated with the bits d.sub.n, the receiver calculates estimates of the bits c.sub.n of the redundant subset as a function of the sign of r.sub.n .multidot.r.sub.f(n). By exploiting the redundancy, the receiver can detect the bits c.sub.n of the subset having erroneous estimates, and rectify the sign of the less reliable of the two associated likelihood data items r.sub.n and r.sub.f(n). The other bits c.sub.n ' of the second sequence then benefit from additional protection if there is at least one bit c.sub.n of the redundant subset such that n'=f(n) or f(n')=n or f(n).

Abstract: At least one fixed beacon is associated with a user of a mobile station and emits, with a range (r) substantially smaller than the characteristic dimension (R) of a cell, a radio signal specific to said user. When the mobile station detects the radio signal emitted by the beacon, the station addresses a signal to the communication network indicating that it is within range of the beacon.

Abstract: The echo canceller comprises an adaptive filter receiving the coefficients of a direct discrete transform into the frequency domain, computed on successive blocks of an input signal and fed via an inverse transform circuit to the subtractive input of an adder for forming an output signal going to the network, and an adaptor circuit for adapting the coefficients of the filter. The adaptor circuit receives the coefficients of successive transforms of blocks of output signal samples via a noise reducer.

Abstract: A pulse timer circuit comprising a monostable multivibrator which includes two complementary transistors Q5, Q6, has the advantage of good tolerance to temperature fluctuation owing to the provision of a Schottky diode D4 connected between the emitter and base of one of the transistors Q5. The Schottky diode, D4, which has a temperature coefficient matched to that of the transistor Q5, ensures that the output pulse width from the monostable is unaffected by fluctuations in ambient temperature.

Abstract: A microwave source has an amplifying transistor capable of operating at microwave frequencies and a frequency selection circuit. The circuit has a whispering mode dielectric resonator and a feedback loop having a first microstrip line connected by an impedance adaptation circuit to a gate of said transistor and a second microstrip line connected by an impedance adaptation circuit to a drain of said transistor. The dielectric resonator is located between the first line and the second line for magnetic field coupling therewith.

Abstract: The apparatus has n non aligned antennas, where n is at least for receiving radio signals from a plurality of OPS satellites. Radio frequency signals received by the various antennas are processed for measuring their phase differences, and for computing attitude on the basis of said phase differences. The measurement and computing system is repeatedly calibrated on the basis of measurements performed by a star sensor during periods when it provides usable data.

Abstract: A method and a circuit configuration for operation of a bus system. A bus includes a bus control unit which controls only an arbitration and when time is exceeded during a data transmission. An actual data transmission is determined in a respective active master unit and an addressed slave unit. A characteristic of a bus cycle, such as a data length, access to a data area or a control area and a waiting cycle, is transmitted in encoded form through a multiplicity of control lines.

Abstract: A line amplifier for static RAM memory in CMOS technology comprises first and second branches formed by a first plurality of transistors (TP.sub.1, TN.sub.1, TN.sub.2) and a second plurality of transistors (TP.sub.2, TN.sub.3, TN.sub.2), respectively. The branches are connected in series between the power supply (Vdd) and reference voltage (Vss). A positive feedback is produced by direct connection through internal nodes, and an evaluation switching transistor makes it possible to equalize the values of the voltages on the internal nodes at equilibrium. Under read control (CL), the transistor (TN.sub.2) makes it possible to amplify the preliminary difference between voltage levels due to a transition of the bit signal (D) and complemented bit signal (D) applied to the internal nodes. A precharge transistor (TN.sub.4) is common to the first and second branches and thus allows an increase in switching speed.

Abstract: The signal received in a CDMA system is sampled at a rate greater than the chip rate of the spreading sequences. In order to assign the propagation delays to the arms of a rake receiver, consecutive delays are tested within a time window by evaluating, for each delay tested, an energy of the correlation between the signal received and a reference spreading sequence to which said tested delay is applied. A selection threshold is determined from the largest of the energies evaluated. A first list is compiled containing delays from the window for which the histogram of the evaluated energies exhibits a local maximum greater than the selection threshold, and a second list is compiled containing delays neighboring the delays of the first list. The delays assigned to the arms of the rake receiver are selected initially from the first list and then, if this is insufficient, from the second list.

Abstract: A high voltage generator including a Marx Generator (1) provides an output of up to 200 kV at a pulse repetition rate of up to 1 kHz. Discharge is triggered by over-volting a first stage (2a) of the Marx Generator, each stage including a hydrogen spark gap switch (5). By inhibiting the charging power supply (7) for a short time after each discharge, recovery of the dielectric is ensured, enabling high repetition rates without the need for gas flow.

Abstract: The attitude of a satellite placed on a non-heliosynchronous earth orbit in a plane that is inclined relative to the equatorial plane of the earth is controlled for efficient use of solar panels and radiators. The satellite has a structure, solar panels apt to be rotated with respect to the structure rotation and two opposed radiators each fixed on one of two opposed faces of the satellite structure which are orthogonal to the rotation axis. One of the radiators has greater emissivity than the other. A yaw axis bound to the structure satellite and orthogonal to rotation axis is aimed towards the earth. The solar panels of the satellite are maintained in an optimum orientation relative to the sun by rotating them. At least during periods of each year when an angle .beta.

Abstract: For controlling the attitude of the body of an earth satellite placed on a low orbit, values of components of the geomagnetic field of the earth are measured along three axes of a frame of reference bound to the body. The values are derivated with respect to time, and multiplied by a gain. Currents responsive to the multiplicated derivatives are passed through magnetic torquers located along the three axes of the body to create magnetic torques that bias the body to a fixed angular position relative to the field lines of the geomagnetic field. Such steps are continuously carried out during eclipse periods. Out of eclipse periods, the pitch of the body is controlled by modifying an internal momentum in response to a signal provided by a solar sensor, so as to maintain solar generators carried by the body of the satellite oriented towards the Sun.

Abstract: A first phase-locked loop (PLL) includes a first integrated voltage-controlled oscillator (VCO) whose output signal has a frequency modulated by an input signal of the device about a multiple of a reference frequency. A second PLL includes a second integrated VCO and frequency transposition means. The transposition circuit receive the output signal of the second VCO and a transposition signal having a non-modulated frequency. The second PLL addresses to the second VCO a control signal capable of aligning the frequency of the output signal of the transposition circuit with the frequency of the first VCO. The output signal of the second VCO forms the frequency modulation transmission signal produced by the device.