Automatic transmit power level control in radio links

Claim 1

1) A transmit power control system in multiline radio links, using microwave signal digital modulation, and specifically the so-called multilevel QAM modulation, the said control is used in multiline radio link systems and specifically in each RF transmitter that receives, from the respective receiver associated therewith, a signal indicating the levels of the useful signals received on that RF channel and sends it back to the said associated transmitter in order to regulate the said transmit power level, characte­rized by the fact that it is comprised of: - means to derive a threshold signal for each RF channel in each receiver, - means to multiplex all threshold signals from the indivi­dual receivers, - means to insert an appropriate signal in the said multi­plexer as necessary to identify the station which it comes from, - means to further multiplex the said multiplexed signal with other service signals, - means to insert this dual-multiplexed signal in the frame of the main information signal sent to the other direction of transmission, - means to receive and demultiplex the received signal two times, - means to process the said demultiplexed signal so as to derive, on one hand, a transmit power level control signal, protected from possible faults or malfunctions of the main transmit digital channel and, on the other hand, the sta­ tion identification signal, - means to apply the said control signal to the pre-distor­tion circuit in the transmit power amplifier.