A communication satellite facility and a satellite communication system adapted to respond flexibly to development and change of communication technologies occurring on the ground even after satellites have been launched. Said layer comprises several components and is insulating, passivating or electrically conductive. The time constant of the time constant circuit comprising a R0 and C is adjusted according to whether a resistor R1 is present or not, and the signals of frequencies f1 and f2 coming out of the sawtooth wave generator 14 are sequentially switched to be sent to the comparator 12.