Frequency ModulationHardQuestion 20310
Question
FM capture effect means that an FM receiver:
- ACaptures only the weakest signal
- BLocks onto the strongest signal and suppresses weaker co-channel signalsCorrect
- CCannot receive two stations simultaneously
- DAlways receives both sidebands equally
Correct answer
Locks onto the strongest signal and suppresses weaker co-channel signals
Explanation
FM capture: if one signal is 3–6 dB stronger than a co-channel interferer, the FM limiter-discriminator captures the stronger signal and essentially ignores the weaker one. This makes FM immune to co-channel interference above a threshold — unlike AM where both signals add linearly. Basis for FM cellular re-use planning.