Abstract: 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).