Which of the following technologies is used for mitigating the effects of jamming?

Frequency diversity is a technique used to mitigate the effects of jamming by spreading signals over a range of frequencies. This approach involves transmitting the same information on different frequencies, which makes it more difficult for a jamming signal to disrupt the communication. If one frequency becomes jammed, the other frequencies may still allow for the successful transmission of data.

By employing frequency diversity, a system can help ensure that its communications remain resilient against intentional interference. This is particularly important in electronic warfare environments, where adversaries may actively employ jamming tactics to disrupt operations.

Other methods such as signal amplification can enhance the strength of a signal but do not specifically address the issue of jamming; active jamming is a countermeasure used to disrupt enemy communications rather than protect one's own; and data encryption secures the content of communications but does not prevent disruption due to jamming. Hence, frequency diversity is uniquely suited to counteracting jamming effects effectively.