Abstract: Embodiments relate to a multiband transceiver apparatus (100), comprising a first transmit path (110) operable to transmit a first transmit signal (sig1) in a first radio frequency band (RF1), wherein the first transmit path (110) comprises an input (112), an output (114) and a first feedback path (116) from the output towards the input of the first transmit path, a second transmit path (130) operable to transmit a second signal (sig2) in a second radio frequency band (RF2), the second radio frequency band (RF2) being different from the first radio frequency band (RF1), wherein the second transmit path (130) comprises an input (132), an output (134) and a second feedback path (136) from the output towards the input of the second transmit path, and a cross-talk canceller (150) operable to cancel cross-talk from the second feedback path (136) to the first feedback path (116) and/or to cancel cross-talk from the first feedback path (116) to the second feedback path (136) of the multiband transceiver apparatus (1

Abstract: The invention relates to a method for synchronizing RF antenna signals (5a to 5i) of a plurality of RF antenna sites (3a to 3i) arranged at different locations of a radio transmission system (1b), the method comprising; generating a reference signal (7) in a reference oscillator (6) located at a central unit (2) of the radio transmission system (1b), transmitting the reference signal (7) as an optical signal from the central unit (2) to the RF antenna sites (3a to 3i) via a plurality of optical fiber links (9a? to 9i?), and using the transmitted reference signal (7) for synchronizing the RF antenna signals (5a to 5i) of the different RF antenna sites (3a to 3i), The invention also relates to a radio transmission system (1b).

Abstract: Embodiments relate to a multiband transceiver apparatus (100), comprising a first transmit path (110) operable to transmit a first transmit signal (sig1) in a first radio frequency band (RF1), wherein the first transmit path (110) comprises an input (112), an output (114) and a first feedback path (116) from the output towards the input of the first transmit path, a second transmit path (130) operable to transmit a second signal (sig2) in a second radio frequency band (RF2), the second radio frequency band (RF2) being different from the first radio frequency band (RF1), wherein the second transmit path (130) comprises an input (132), an output (134) and a second feedback path (136) from the output towards the input of the second transmit path, and a cross-talk canceller (150) operable to cancel cross-talk from the second feedback path (136) to the first feedback path (116) and/or to cancel cross-talk from the first feedback path (116) to the second feedback path (136) of the multiband transceiver apparatus (1

Abstract: The invention relates to a method for synchronizing RF antenna signals (5a to 5i) of a plurality of RF antenna sites (3a to 3i) arranged at different locations of a radio transmission system (1b), the method comprising; generating a reference signal (7) in a reference oscillator (6) located at a central unit (2) of the radio transmission system (1b), transmitting the reference signal (7) as an optical signal from the central unit (2) to the RF antenna sites (3a to 3i) via a plurality of optical fiber links (9a? to 9i?), and using the transmitted reference signal (7) for synchronizing the RF antenna signals (5a to 5i) of the different RF antenna sites (3a to 3i), The invention also relates to a radio transmission system (1b).

Abstract: A method of controlling a tuneable filter (13a) of an antenna network (13) for use in a base station (1). The proposed method comprises: inputting an output of the antenna network (13) to a pre-distortion feedback path (5), inputting an output of the pre-distortion feedback path (5) and part of an original baseband signal to be transmitted by the base station (1) to a tuneable filter optimization algorithm (20a), controlling the tuneable filter (13a) in accordance with an output (CS) of said tuneable filter optimization algorithm (20a).

Abstract: A method of controlling a tuneable filter (13a) of an antenna network (13) for use in a base station (1). The proposed method comprises: inputting an output of the antenna network (13) to a pre-distortion feedback path (5), inputting an output of the pre-distortion feedback path (5) and part of an original baseband signal to be transmitted by the base station (1) to a tuneable filter optimisation algorithm (20a), controlling the tuneable filter (13a) in accordance with an output (CS) of said tuneable filter optimisation algorithm (20a).

Abstract: A method of sideband suppression for an I/Q modulator as well as an electronic circuit for sideband suppression, a transceiver, a base station and a mobile station making use of the electronic circuit in the framework of wireless telecommunication and digital communication networks. The inventive method of sideband suppression is based on a two step modulation scheme, where a baseband signal is modulated by means of two modulators to an intermediate frequency signal, which in turn is modulated to a RF signal by means of an analog I/Q modulator. The invention provides adaptive and dynamic tuning of the phase of the intermediate frequency signal, preferably by making use of two CORDIC modules as modulators that are driven by a phase accumulator. Additionally, a control unit serves to tune the phase of the intermediate frequency signal in response to detect an undesired sideband signal in the RF output of the I/Q modulator.

Abstract: A mechanical switching circuit for connecting or disconnecting the connection between a circuit input and a circuit output comprises at least two switching units connected in series and each of the switching units comprises at least two mechanical switching components connected in parallel.

Abstract: A telecommunication device (11) for vehicle installation is proposed, which is equipped with an HF-transmitting and receiving device (22, 23), with different terminals and with a transmission network (19) between the HF-transmitting and receiving device and the terminals. The telecommunication-specific part of each terminal is physically separated from the actual user part (12, 13, 14) of the terminal, and installed in a central terminal control (15), which is connected with the HF-transmitting and receiving device (22). An efficient, optical transmission network (19) may be provided between the terminal control (15) and the user parts (12, 13, 14) of the terminals. Both the central terminal control (15) and the user parts (12, 13, 14) of the terminals are equipped with an interface unit for the transmission network (19). The telecommunication device (11) is less voluminous than a conventional device with individual terminals, and therefore more suitable for installation in the vehicle.

Abstract: To assign a carrier frequency to different mobile stations in a conventional Space Division Multiple Access (SDMA) radio system, the stations are differentiated according to the direction in space from which they transmit radio signals to a base station. In addition, the distances between the base station and the mobile stations are compared. To prevent interference at the receiving site (base station BTS), according to the invention a carrier frequency (f) is assigned to the different mobile stations (MS1 to MS3) only if the directions in space (.THETA.1 to .THETA.3) are sufficiently different and the receive levels (P1 to P3) of the radio signals are sufficiently equal. To that end, each mobile station (MS1 to MS3) is assigned a guard area, which encompasses at least a preselected solid angle (lobe width w) and at most a preselected level space (dynamic range S).

Abstract: A frame-structured bus system, particularly for a local operation network for automotive applications, is disclosed in which a plurality of bus stations share a data bus, and in which one of the bus stations generates a sequence of data frames of constant bit length. Each data frame includes an isochronous frame module and an asynchronous frame module, and the division of each data frame into the isochronous and asynchronous frame modules is dynamically variable. The message transmitted by a station is passed through a central star coupler to all stations.