Patent ID: 7362827

Claim:
A method for decoding of a signal in an interrogation/response type of communications system, a received signal being formed by a video signal S vh , S vb and a signal S dh , S db containing the data said signals respectively corresponding to the signals received at the high antenna 1 h of the receiver and at the low antenna 1 b of the receiver of an IFF (identification Friend or Foe) said data signal being a MSK (Minimum Shift Keying), FSK (Frequency Shift Keying) or DPSK (Differential Phase-Shift Keying) modulated signal wherein the method comprises the following steps: signals S dh (Fl), S db (Fl) converting the intermediate frequency analog signals into a digital signals, by using a comparator having a threshold set as a function of the S dh (Fl), S db (Fl) signals; sampling the digital signals signals S eh , S eb at a given frequency Fe to obtain S eh , S eb , then sending the signals S eh , S eb to a filter adapted to readjusting the frequency of the sampled signals S eh , S eb towards a frequency included in the frequency band of the initial signals S dh (Fl), S db (Fl); transmitting the video signals S vh , S vb to pulse detectors; and transmitting the sampled and filtered signals S eh , S eb as well as outputs of the pulse detectors to a processing step so as to determine the initially received signal to a demodulating step adapted to produce original binary of the signal.