AdvancedA-005-006-011

Intermodulation interference products are not typically associated with which of the following:

B
Answer
Antennas and transmission lines
Type
A
receiver frontend
B
intermediate frequency stage
C
passive intermodulation
D
final amplifier stage

Answer Notes

Intermodulation (IMD) occurs when two or more signals mix in a non-linear component, creating unwanted spurious products. This typically happens in front-end receiver stages that are overloaded by strong out-of-band signals, or in transmitter final amplifier stages being driven into non-linear operation. Passive intermodulation (PIM) is also a known issue, occurring in rusty joints or degraded connectors in the antenna system where dissimilar metals create a diode-like mixing effect. However, the Intermediate Frequency (IF) stage is usually highly filtered and protected by the receiver's front-end and mixer stages. Because only a very narrow band of desired frequencies makes it through the filters to the IF stage, the strong off-frequency signals required to cause intermodulation are already stripped away, making IMD highly unlikely there.
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