In telecommunication, a capture effect is a phenomenon, associated with FM reception, in which only the stronger of two signals at or near the same frequency will be demodulated.

Note 1: The complete suppression of the weaker signal occurs at the receiver limiter, if it has one, where it is not amplified, but attenuated.

Note 2: When both signals are nearly equal in strength, or are fading independently, the receiver may switch from one to the other. Synonym FM capture effect.

Source: from Federal Standard 1037C and from MIL-STD-188