Alcatel Telspace

Alcatel Transmission Par Faisceaux Hertziens

Alcatel Transmission Par Faisceaus Hertziens A.t.f.h.

Patrick Janer

Xavier Roubinet

Serge Szczepanowski

The invention concerns a method of transmitting data reliably over N normal channels (3), where N.gtoreq.1, and over at least one back-up channel (4), between a transmit end station (1) and a receive end station (2), the data transmitted comprising both traffic data and supervisory data. According to the invention, the following successive steps are performed in said transmit end station (1): the traffic data and the supervisory data applied to each of the N pairs of inputs are multiplexed on a respective one of the N normal channels; then, the multiplexed data from a 'backed-up' one of the N normal channels is switched to the back-up channel. The following successive steps are performed in the receive end station (2): the multiplexed data from the back-up channel is interchanged with the multiplexed data from the backed-up normal channel; then the traffic data and the supervisory data on each of the N normal channels are demultiplexed so as to make the data available at a respective one of the N pairs of outputs.

Method of transmitting data reliably over N normal channels, and over at

Apparatus for correcting quadrature error in a quadrature modulator and/or in a demodulator for a signal having a plurality of phase states, or of amplitude and phase states. The correction apparatus comprises a processor (51) which, when the apparatus is used to correct quadrature error in a demodulator, transforms the levels P and Q of the digital signals output by the demodulation stage into corrected levels P' and Q' that satisfy any one of the following eight relationships: ##STR1## These corrected levels are then applied to decision element (72), optionally after their maximum levels have equalized. The apparatus combines correction accuracy with cheapness, and it enables any quadrature error to be corrected.

Apparatus for correcting quadrature error in a modulator and/or in a

Process for digital transmission and direct conversion receiver

The invention provides a digital radio link receiving device consisting of a microwave frequency part with a device for signal downconversion to an intermediate frequency, an intermediate frequency part limited to direct demodulation of the signal at intermediate frequency, and a baseband part responsible for processing the signal.

Digital radio link receiving device

A microwave frequency group delay corrector operates by reflecting the microwave on a correcting complex impedance (jx). It makes use of a power divider (13), of the Wilkinson type. The complex impedance (20) is connected to the port (14) which is normally the inlet port to the power divider (13). The microwave (E) is applied to one of the other two ports (15), and the remaining other port (16) is used as the port from which the phase corrected outlet microwave (S) is taken.

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Levallois-Perret, France

Patrick Janer