About Using Two-Level Probing Signal in Nonlinear Radio Location
A probing signal represented by two successive radio impulses having the same amplitude but different energies is suggested for application in pulsed nonlinear radars, while for the receiver it is suggested to perform either correlation processing or optimal filtering of each of the reflected signal components at the carrier frequency. Due to the fact that the response of the optimal filter is proportional to the energy of the pulsed signal, the response levels of the two impulses reflected from an object lacking nonlinear properties will be equal. Should an object have nonlinear properties the response levels at the optimal processing device output at certain moments of time will be different thus indicating that a nonlinear object has been detected. Since the energies of the probing signal components are equal and optimal filtration is performed when receiving the reflected signal, this ensures that the noise interference equally affects the error while comparing levels of the received signal components. Depending on the error magnitude it is necessary to select upper and lower limits of the amplitude uncertainty within which response levels can be considered different. Decision about the presence of the nonlinear object is made if the difference in response levels goes beyond these limits. Suggested below is a block diagram of a decision-making device based on a successive correlation processing of each of the received signal components where the response level of the correlator at the moment when impulse ends is stored until the time when the decision is made i.e. when the second impulse ends.