<p>The invention relates to a power control device for a power output stage. A forward signal corresponding to a wave advancing on a wall feed line and a return signal corresponding to a wave returning on the wave feed line is obtained by means of a directional coupler and is supplied to a controller after narrow-band selection for controlling the output of the power output stage. Narrow-band selection is not carried out in the baseband but on an intermediate frequency level above the baseband.</p>
