Abstract: A positioning method for a mobile station in the radio coverage area of a satellite entails determining the instantaneous distance between the satellite and the mobile station. The instantaneous elevation angle .phi. of the satellite is then calculated from the instantaneous distance, the altitude of the satellite and the radius of the Earth. The Doppler shift .delta. is then determined, after which the angle .theta. between the projections onto the surface of the Earth of the track of the satellite and a straight line segment passing through the satellite and the mobile station is calculated from the Doppler shift .delta. and the instantaneous elevation angle .phi.. The location of the mobile station is then determined from the instantaneous distance, the instantaneous elevation angle .phi. and the angle .theta..

Abstract: A microcontroller integrated circuit comprises a processor core which exchanges data with at least one data processing and/or storage device. The integrated circuit comprises a mask-programmed read only memory containing a generic program such as a test program which can be executed by the microcontroller. The generic program includes a basic function for writing data into the data processing and/or storage device or devices. The write function is used to load a downloading program. Because a downloading program is not permanently stored in the read only memory, the microcontroller can be tested independently of the application program, and remains standard with regard to the type of memory component with which it can be used in a system.

Abstract: The present invention relates to a dummy burst structure used in a cellular digital radio-communications system operating on the principle of time division multiple access, each cell in the system being associated with a beacon frequency subdivided into periodically-repeated frames, each of which comprises at least one signalling channel or beacon path for transmitting signalling messages to mobile stations, the other channels serving in particular to transmit useful data, the burst being transmitted over those channels of the beacon frequency which are not assigned to transmitting useful data, or over certain time slots of the signalling channel when there is no signalling data to be transmitted over the certain time slots, wherein the burst contains a signalling message.

Abstract: The analog-to-digital converter receives an analog input signal (x(t)) to produce a digital error signal (y(t)).It comprises a subtractor (1) to calculate the difference between the input signal and a reference signal (Ur(t)), a converter subsystem (2, 3, 4) to produce the error signal from said difference and a feedback loop to produce the reference signal by means of a digital-to-analog converter (5) which delivers a comparison signal (Uc(t)) in response to the error signal.In accordance with the invention, the input signal (x(t)) is assigned a center frequency (f.sub.0), the feedback loop comprises a displacement unit (7) for displacing the frequency response of the digital-to-analog converter (5) from the null frequency towards the center frequency (f.sub.0), said displacement unit producing the reference signal (Ur(t)) from the comparison signal (Uc(t)).

Abstract: A dual mode portable digital radio transceiver for communicating via a terrestrial network (first mode) and via a satellite network (second mode) synthesizes a modulation first frequency for modulation of signals transmitted in both modes and a conversion second frequency for demodulation of signals received in the two modes. It divides the conversion second frequency supplying a conversion third frequency for demodulation of signals received in one of the modes using a signal receive frequency band far away from the other frequency bands used. It is therefore possible, using a single synthesized pure carrier, to carry out direct conversion in a first mode and intermediate frequency conversion followed by the same direct conversion in the second mode.

Abstract: A method of constructing a spreading code associated with one user of a direct sequence code division multiple access digital transmission system includes at least one stage of concatenating a plurality of different sub-codes. Specifically, the spreading code is constructed by concatenating at least two different, in particular, cyclically different, basic sub-codes belonging to the same family of basic sub-codes, and at least one secondary sub-code obtained by circular permutation of one of the basic sub-codes. The constructed spreading code is then designated as being associated with the one user.

Abstract: In a method of determining, in a cellular mobile radio system with more than one type of cell, which type of cell a mobile station is accessing, the management network of the system sends to the mobile station a signalling message (recognition message) in the form of a sinusoid whose frequency (recognition frequency) differs from a reference frequency known to or determinable by the mobile station. The difference, optionally a null difference, between the reference frequency and the recognition frequency is characteristic of the cell type. The mobile station determines the recognition frequency. The mobile station then determines the difference between the reference frequency and the recognition frequency. The mobile station then determines the cell type from this difference.

Abstract: A threshold detector for digital signal transmission systems using a transmission channel, in particular for transmission to mobiles, calculates a set of coefficients f.sub.n belonging to the group comprising a set of coefficients c.sub.n of the correlation between a first series of digital samples x.sub.n received by the receiver and a second series of reference digital samples p.sub.n known to the receiver, in order to acquire synchronization of the system, and a set of coefficients h.sub.n of an estimate of the impulse response of the transmission channel, when the system is already synchronized. It also calculates a decision variable A such that: ##EQU1## where L and N are predetermined integers. The device has many applications in mobile radio systems, for example for acquisition of synchronization in DS-CDMA systems or for optimizing the transmission channel estimate.

Abstract: In multiplexed data radio communication, especially (but not exclusively) in TDMA mode, a method is provided of offering optimized intelligent traffic channel sharing services, enabling data from a secondary source to be conveyed on a traffic channel assigned to a main source (20, 30, 40). Each of the blocks transmitted by the main source and the data from the secondary data source are defined by one of the least three relative levels of importance (NI.sub.p =0, 1 or 2; NI.sub.s =0, 1, or 2). Data from the secondary source is substituted for a block transmitted by the main source as the result of a comparison of the respective relative levels of importance of data from the secondary source and the block from the main source.

Abstract: A differential current mode amplifier device generates a common mode bias current. A translinear multiplier receives at two inputs this common mode bias current and a differential mode current to be amplified and delivers at two outputs an amplified differential mode current. The translinear multiplier is biased in a manner depending on the bias current received by the translinear multiplier. The device includes a circuit for compensating the common mode current at the output of the translinear multiplier.

Abstract: A current-mode amplification system including a first gain section and at least one second gain section chained together to form a chain of gain sections. The first gain section containing a first amplifier and a first low-pass filter. Each second gain section contains: a second amplifier having (1) a first input receiving the amplified and filtered output current from the preceding gain section in the chain, and (2) a second input receiving an input current of the amplification system, and delivering an amplified output current; an activator/deactivator for activating/deactivating the second input; and a second low-pass filter, the low-pass filter of each of the chained-together gain sections having a high cut-off frequency, the high cut-off frequencies of the various gain sections increasing from the input to the output of the amplification system.