Which term describes interference that occurs when a very strong signal interferes with other signals in the received mix?

• A. Intermodulation distortion.
• B. Cross-modulation interference.
• C. Receiver quieting.
• D. Capture effect.

Answer: (B)

Cross-modulation interference happens when a very strong signal in the receiver causes nonlinear circuitry to imprint its modulation onto other signals that are present. Because the receiver front end and other stages aren’t perfectly linear, the strong signal can distort the response of nearby weaker signals, effectively modulating them with the strong signal’s own modulation. The result is distortion or interference on those weaker channels without creating new frequencies in the spectrum—the interference is the weak signals being modulated by the strong one. This is different from intermodulation distortion, which involves generating new sinewaves at sum and difference frequencies from mixing signals, and from capture effect, where the strongest signal simply dominates the output. It’s also not described by receiver quieting, which is a broader loss of signal rather than targeted modulation of one signal by another.