Matra Communication

Societe Anonyme Dite Alcatel Telspace

Jacques Peltier

Gottfried Schnabl

In order to correct nonlinearities of an amplifier which receives a radio signal and produces an amplified radio signal representing an input complex digital signal, a predistortion table, associating a value of a predistorted complex digital signal with each value of the input complex digital signal, is stored, and the predistorted complex signal is modulated in order to obtain the radio signal addressed to the amplifier. In an adaptation period, a fraction of the amplified radio signal is demodulated in order to obtain a demodulated complex signal which is compared with the input complex signal, with which the predistorted complex signal modulated in said adaptation period is associated, in order to update the predistortion table. The input complex signal or the predistorted complex signal has a phase which is constant modulo .pi. in the adaptation period.

Method of correcting nonlinearities of an amplifier, and radio

In order to correct nonlinearities of an amplifier which receives a radio signal and produces an amplified radio signal representing an input complex digital signal, a predistortion table, associating a value of a predistorted complex digital signal with each value of the input complex digital signal, is stored, and the predistorted complex signal is modulated in order to obtain the radio signal addressed to the amplifier. In an adaptation period, a fraction of the amplified radio signal is demodulated in order to obtain a demodulated complex signal which is compared with the input complex signal, with which the predistorted complex signal modulated in said adaptation period is associated, in order to update the predistortion table. The predistortion table is updated on the basis of mean values calculated from blocks of samples of the input complex signal and of the demodulated complex signal, which are stored in the adaptation period.

In a method of detecting false-locking the trains of clock signals corresponding to the two phase offset initially modulated trains of signals, the phase offset between said trains of clock signals is monitored, and false-locking is detected when the phase offset changes signal. Also, a method of demodulation implements this method of detecting false-locking. Also, a device for implementing the method of detecting false-locking contains a flip-flop in series with a monostable.

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Jacques Peltier