Abstract: A system for verifying an operation in particular one that includes payment, the system comprising at least one terminal (11) and a plurality of portable objects (10) which may be coupled, preferably without contact, to the terminal. The terminal emits repeated interrogation messages suitable for triggering reading of the contents of a shift register (60, 190) in a portable object when said object is coupled thereto, only after a comparator has verified concordance between first validity data from the portable object and check data from the terminal. After processing, the terminal re-writes updated useful data in the register. Re-writing is only authorized after a comparator (240) has verified concordance between second validity data stored in the shift register with check data transmitted by the terminal into a register (220) of the portable object. The check data is produced by the terminal after decoding the validity data contained in the message derived from reading the portable object (10).

Abstract: The counter circuit is adapted to counting high frequency pulses and to being read while counting said pulses. It comprises a plurality of pulse counting stages of increasing numerical significance, and read means for reading the states of said stages. Said plurality of pulse counting stages comprises lower significance stages (10.sub.1 to 10.sub.4) connected as a synchronous counter (10) and higher significance stages (12.sub.1 to 12.sub.n) connected as a ripple counter (12). The synchronous counter is so connected that it counts the high frequency pulses (H) directly, and that any change of state required in any of its stages on counting a pulse occurs substantially simultaneously with the arrival of said pulse. The ripple counter is so connected that it counts count cycles of the synchronous counter, and that it takes a long time relative to the interval separating two successive high frequency pulses for a change of state to propagate, where necessary, from the least significant stage (12.sub.

Abstract: A bus line installation for the transmission of informations between a plurality of transmitters and a plurality of receivers.The signals transmitted by the bus line are optical signals. Each receiver comprises opto-electronical means for the transformation of optical energy into electrical energy and means for bringing the electrical signals representative of said transformation to the shape for which a part of the receiver similar to that of a bus line installation transmitting electrical signals is operative.

Abstract: Apparatus for acquiring and processing incoming radio signals received from a plurality of stations, the frequencies of which are contained in a predetermined frequency band.The received signals are mixed with a local oscillator frequency which is repeatedly scanning the input frequency band at a fast rate produced from a frequency synthesizer whose control input is modified step by step to cycle through a corresponding predetermined set of programming values. The sweep rate of the programming value of the frequency synthesizer is so high that the stabilization time for the frequency at its output is significant with respect to the dwell time of the control signal of each programming value.The varying frequency signals at the output of the mixer are applied to the inputs of band pass filtering channels, to derive the frequency range of the incoming signals for frequency selective circuitry arranged to demodulate the received signals.

Abstract: An apparatus for receiving messages transmitted from a plurality of radio signal sources operating at different frequencies within a predetermined frequency band. Means are provided to frequency scan the receive signals, deriving information for determining the frequency range in which said signals lie. A demodulating phase locked loop is connected to receive the radio frequency signals, and an initial operating frequency for the phase locked loop is provided by the frequency range information determined from the means for frequency scanning. A resetting circuit is included to maintain the phase locked loop oscillator frequency at a value independent of the frequency of the radio signals.

Abstract: An apparatus for acquiring and collecting messages aboard a satellite which are transmitted via respective radio-signals over different frequencies from a plurality of beacons comprises a receiver having an adjustable gain control input. An automatic gain control loop is provided for maintaining the gain of the receiver at a constant value. While the input frequencies of each input signals and time of arrival thereof are not exactly known, it is known that all these input frequencies are contained within a predetermined input frequency band which is periodically scanned by a frequency analyzer. This analyzer operates by scanning the center frequency of a band pass filter over the input frequency band and detecting the level of signals at the output of this filter for a plurality of successive frequencies within this input frequency band. The detected levels are digitized.

Abstract: An electrical contact device is provided for use in establishing an electrical connection between an access terminal and an electronic card which may be inserted in the access terminal. The access terminal has contact members which are movable in a direction transverse to the surface of the card to establish electrical connection with terminal contact areas on the card. Prior to operating the electrical connection established between the access terminal and the card for a transaction, the conductive quality of the connection established with each card contact zone is tested by providing each contact member in the form of two pins engaging each contact zone of the card at two respective spaced apart zones and performing a measurement of the ohmic resistance of the circuit thus established through said contact zones. If the resistance measured is too high, a cleaning current may be passed through this circuit. If the resistance measured remains too high, a warning signal is made to appear at the terminal.

Abstract: An access trial control device for a card, such as a financial or business transaction card or the like, which is inserted in an access terminal for use and carries a confidential code which is compared with an access code type by the user on the terminal. For each access trial the result, acceptance or refusal, of the comparison is permanently recorded by non volatile memory means in the card. The number of consecutive access trials refused is counted in a counter and is detected by a control circuit which disables the card when such number reaches a predetermined value. Each accepted access trial resets the counter to zero.

Abstract: A transistor integrated circuit particularly for use in transaction cards such as credit cards or payment cards comprises conductive film zones on the surface of the circuit having a shape and layout which makes it difficult or impossible to determine the layout of the circuit. Additional metal zones may be formed at the level or below the level of the transistor connection strips, which cannot be eliminated without eliminating the strips. Alternatively, instead of strips, metal zones extended in two dimensions are used whereby their junction to an underlying transistor may not be easily located by observing their surface by microscopic means.

Abstract: In a transaction card such as a credit or payment card provided with an integrated circuit for performing and recording the transaction, communications between the card and an access terminal must be coded so as to prevent fraud attempts. An integrated circuit coding device for coding or decoding a message in accordance with a confidential coding key comprises active transistors, and passive transistors, i.e. permanently blocked and/or permanently conductive, interconnected in such a way that observation of such circuit by means of an electronic microscope does not allow the determination of the confidential key which is implemented by the circuit.

Abstract: The apparatus gives an indication of the location in time between two successive clock signals of an event to be timed. Such an event may be the arrival of a laser pulse at a satellite. An integrator circuit (C84) is charged by a relatively high charging current from a first current generator (66) during the period of time between the event and the next clock signal. The integrator circuit is then discharged by a smaller current of opposite sign from a second current generator (80). The ratio of the charge and discharge currents "stretches" the inter clock pulse time interval to a length that can be measured by counting clock pulses as the integrator discharges. For this factor to be useful, it is essential that the charging current remains constant during charging and from one charging occasion to the next. This is achieved by keeping the generator (66) generating current constantly and by diverting the current through an integrator circuit by-pass (R78) when not integrating.

Abstract: In a satellite which asynchronously receives radio frequency signals from a lurality of beacons scattered at the surface of the earth, each signal received has a pure carrier wave portion followed by a phase modulated message carrying portion. The frequencies of the signals are not known within a predetermined frequency band. The satellite has a plurality of essentially identical processing units which each receive on their input all the signals present at any given instant in the input frequency band. Each processing unit has a phase locked loop which may be progressively tuned to the frequency of one of these input signals in response to a frequency estimate of this signal to which the operating frequency of the phase locked loop is preset. This frequency estimate is updated until the phase lock occurs on this input signal, ready for demodulation of the message part to begin. The estimate frequencies are derived from an input band frequency spectrum analyzer.

Abstract: An arrangement for controlling a telephone transmission line having an input linked to a sound detection device located in a noisy environment. The transmission line operates only for the transmission of words received by the sound detection device. The transmission line is made operative or inoperative according to whether sound energy variation collected by the sound detection device for duration of a predetermined time interval is superior or inferior to a predetermined approximate audio level.

Abstract: A system for measuring the distance between an interrogating station and a transponder station comprises, at the latter station, a receiver for a phase-modulated UHF wave emitted by the interrogating station and a transmitter for sending back an outgoing main carrier modulated in phase by a locally generated subcarrier. A first oscillator generates a wave whose frequency is a subharmonic of the frequencies of both the incoming and the outgoing main carrier and from which there are derived, besides this outgoing carrier, a heterodyning oscillation and a reference oscillation which are both amplitude-modulated by the output of a second oscillator whose frequency matches that of the incoming subcarrier and which also serves as a source of the locally generated outgoing subcarrier.

Abstract: The time interval between the pulses of an interrogation signals transmitted to aircraft in the vicinity of an airport is varied at will in accordance with air traffic conditions. The time interval under heavy traffic conditions may be varied from its nominal value as a function of the rate of response signals, the garbling rate thereof, or the decoding rate. The time interval may be controlled manually as a function of air traffic conditions displayed on a screen associated with the interrogator and receiver. By varying the time interval the percentage of responses to interrogation may be varied to optimize overall reception conditions and utilization of potentially available information.

Abstract: A process and apparatus for the detection of an object in air, wherein a beam of electromagnetic radiation is emitted, the reflected beam is received, the frequency of the reflected beam being varied discontinuously over a frequency band. The amplitude of the energy of the beam received for the various frequencies of the emitted beam is measured so as to utilize, for the detection of the object, the particular frequency or frequencies of the beam for which the reflected beam possesses a substantially higher energy than the energy of the beam reflected at the other frequencies.

Abstract: A flat radar antenna comprises a generally circular array of juxtaposed radiators constituted by slotted waveguides, the array being divided into four quadrants each composed of a multiplicity of groups of radiators. The radiator groups of the entire array are connected to a high-frequency transceiver via parallel paths of identical electrical length, consituted in one embodiment by cascaded couplers of magic-T type, whereby the bandwidth of the antenna equals that of each group so as to facilitate frequency scanning.

Abstract: Flat radar antenna for radar apparatus comprising a plurality of aligned radiating elements disposed in parallel rows, in which the quantity of energy flowing between each one of said elements and the radar apparatus can be adjusted, characterized in that said radiating elements are waveguides with coplanar radiating faces, said waveguides being grouped according to four quadrants, each one of said quadrants being connected with the radar apparatus by means of a feed device adapted to take on one of two conditios, one in which it feeds all the waveguides in the quadrant and the other in which it feeds only the rows nearest to the center of the antenna excluding the other waveguides in the quadrant, means being provided for the four feed devices to take on at the same time the same condition, so that the radar antenna emits a radar beam which is symmetrical relatively to the center of the antenna, and having a different configuration according to the condition of the feed devices.

Abstract: An amplifier for an electromagnetic radiation receiver has a plurality of amplification channels for the determination of angular separations, especially for use in self guiding equipment in missiles in which each amplification channel has several amplification stages each of which is of fixed gain. Means are provided to vary the number of operational stages as a function of the sum of the outputs of the channels. A converter is disclosed for converting the analog signal values to stochastic values. A division process is disclosed for the data, based on the use of simple operator and stochastic values.

Abstract: Apparatus for phase keying in frequency and phase voltage controlled oscillator with an incoming signal having a T period phase coded of the biphase PCM or PSK type.The apparatus comprises a circuit loop for phase controlling the oscillator with logic circuitry and first and second conductive paths. Each of the first and second conductive paths have integrators. The integration time of the first and second integrators is equal to the period T of the incoming signal. The limits of integration of the first integrator are - T/8 and + 7T/8 and the limits of integration of the second integrator are + T/8 and + 9T/8. A delay element is disposed between the logic circuitry and the second conductive path introducing retardation time of T/4.