Abstract: A circuit and method for supplying an electronic circuit with a direct supply voltage using high frequency antenna signals. The method includes producing a primary direct voltage equal to a fraction of the supply voltage using at least one antenna signal, producing at least two pumping signals having a frequency lower than the frequency of the antenna signals by means of an oscillator electrically powered by the primary voltage and boosting the primary voltage by means of a charge pump driven by the pumping signals, to obtain the supply voltage.

Abstract: A circuit and method for supplying an electronic circuit with a direct supply voltage using high frequency antenna signals. The method includes producing a primary direct voltage equal to a fraction of the supply voltage using at least one antenna signal, producing at least two pumping signals having a frequency lower than the frequency of the antenna signals by means of an oscillator electrically powered by the primary voltage and boosting the primary voltage by means of a charge pump driven by the pumping signals, to obtain the supply voltage.

Abstract: A semiconductor packing substance for an undersea cable transporting electrical power, said cable having a core made of conductors 1 disposed axially, surrounded by a polyethylene layer 3 which is made semiconductive, then by a layer of insulating polyethylene (4). The packing substance is obtained by reticulating liquid nitrile rubber with carboxylic bonds and an epoxy resin to both of which is added a carbon black with a specific surface area at least equal to 100 m.sup.2 /g, an anti-oxidizing agent and a reticulation accelerator.

Abstract: Sealed power cables (e.g. for underground or submarine use) are often equipped with a metal sheath. A problem with some such cables is that their insulation is subject to greater thermal expansion of the cable during use than the metal sheath is capable of following. According to the present invention the metal sheath (5) is longitudinally corrugated either when the metal sheath is manufactured or by pressing a metal sheet which is originally plane over resilient ribs disposed longitudinally on the cable.