The invention relates to a device for determining the level of an input
signal (101) intended to be applied to a receiving
system (TUN), said receiving
system (TUN) comprising arranged in series a set of discrete
gain amplifiers (102-103-105-107), a
selective filter (104), a mixer (106), said receiving
system (TUN) being intended to deliver an output
signal (108), said device comprising: measuring means (116) for measuring the level of said output
signal (108) in a given frequency channel, means (120) for determining the real
gain (G1) of said set of amplifiers (102-103-105-107) in said given frequency channel, means (121) for determining the real
gain (G2) of said
selective filter (104) in said given frequency channel, calculation means (122) for deriving the level of the input signal (101) from the level of the output signal (108), the real gain (G1) of said set of amplifiers (102-103-105-107) and from the real gain (G2) of said
selective filter (104).