Studies on the effect of unwanted signal modulation depths on interference in the receiver

It is well known that when two strong undesired signals reach the non linear circuit at the receiver input there will be interference at the receiver output. When the receiver is tuned to a desired signal in its absence both the interference signals appear simultaneously in the receiver output. Due to the non-linear characteristics of certain elements like transistor, diode frequency conversion takes place which creates components of frequencies for which receiver reacts. When the sum or difference of interference frequency equals the tuning frequency the damage is more prominent. In this case, the interference signals which is generated, is converted into an intermediate frequency along with the desired signal. In this paper the mathematical analysis of intermodulation phenomenon is presented in order to find some effects of unwanted signal modulation in the generation of interference. The variation of unwanted signal as a function of modulation depth is presented.