Abstract: The present invention concerns a receiver (110) including: an antenna (2) able to receive a frequency shift keying modulated signal (S), conversion means (3) able to receive this signal and to provide two first analog signals (I, Q); and demodulation means (112) able to receive said first signals and to provide a signal (X32+Y32) representative of the modulated signal. This receiver is characterised in that the demodulation means comprise: a complex filter (116) able to receive the first analog signals and to provide two second analog signals (X3, Y3), so that the gain of the transfer function (H3) can be equal to two different values (G1, G2); two normalisation means (118, 120) able to receive the second signals, and to provide in response two third analog signals (X32, Y32), representing a standard of the second signals; and an adder (122) able to receive said third signals and to provide the sum thereof.