A satellite system includes a radio frequency signal amplifier device comprising a control and supply module and a plurality of travelling wave tubes. The module is configured to apply to at least one of the tubes an anode voltage operating value, generating a cathode current in response. The module is moreover configured to measure at least one sum of the cathode currents that is associated with the plurality of tubes, the at least one measurement of the sum of the cathode currents being implemented on the basis of a single measuring circuit, and to determine at least one corrected anode voltage operating value, associated with the at least one of the tubes, on the basis of the at least one measurement of the sum of the cathode currents.