Which practice helps prevent intermodulation products in RF front ends?

• A. Using wideband amplifiers without filtering
• B. Reducing shielding of cables
• C. Ensuring system linearity and applying filtering
• D. Maintaining high nonlinearity

Answer: (C)

Intermodulation products arise when RF front-end devices operate nonlinearly while multiple signals are present. The way to prevent them is to keep the system operating linearly and to remove potential mixing signals with filtering. By ensuring linearity—providing enough headroom, avoiding compression, and using components with good linearity (high IP3)—the generation of new frequencies from mixing is minimized. Filtering further reduces intermodulation by attenuating out-of-band signals before they reach nonlinear stages, preventing those signals from participating in any mixing. Together, these practices keep the front end from producing unwanted frequencies and help protect receiver performance. Using wideband amplifiers without filtering would allow strong off-band signals to drive nonlinearity, reducing shielding isn’t a fix, and maintaining high nonlinearity would worsen the problem.