A method and system are provided for generating high and low-frequency components for the pixels of a detector array. The cavity furthermore has an internal wall with at least one region made of an initial material. A microcontroller compares these measurements and adjusts a variable attenuator in the transmission signal path and a variable attenuator in the received signal path to compensate for signal level variability due to variations in signal loss. A rear-side portion of the spring material 71 is mounted on a rear-side spring mounting member 72 below the backrest seat 2. For example, the despreading factor used is equal to sixteen, with the maximum possible number of de-channelization codes used being equal to five, ten or fifteen, depending on the capability class of the station.