Which option describes coherent jamming?

Which option describes coherent jamming?

• A. Modulation of a signal with intelligible data that can be broken out and interpreted
• B. Modulation of incoherent to random pattern of bits that does not contain data
• C. Spreading the signal across a wider bandwidth
• D. Single-tone jamming at the target frequency

Answer: (A)

Coherent jamming means the jammer locks onto the exact same signal being received, matching its carrier, phase, timing, and often the data content. By transmitting a replica of the target waveform that carries intelligible data, the jammer creates a correlated interference at the receiver. The result is a superposition of two coherent copies of the same information, which is much harder to separate or filter out than random noise. This is why the option describing a jamming signal that contains intelligible data that can be broken out and interpreted best captures coherent jamming—the jammer is effectively reproducing a usable version of the target signal to degrade reception. The other approaches describe non-coherent or different jamming strategies: a random, data-less pattern is incoherent noise; spreading the signal across a wider bandwidth is spread-spectrum use, which reduces power density but isn’t about coherent interference with the same data; and a single-tone jam is a simple interference at the carrier, not necessarily phase-locked to the target signal or carrying the same data.

Coherent jamming means the jammer locks onto the exact same signal being received, matching its carrier, phase, timing, and often the data content. By transmitting a replica of the target waveform that carries intelligible data, the jammer creates a correlated interference at the receiver. The result is a superposition of two coherent copies of the same information, which is much harder to separate or filter out than random noise. This is why the option describing a jamming signal that contains intelligible data that can be broken out and interpreted best captures coherent jamming—the jammer is effectively reproducing a usable version of the target signal to degrade reception.

The other approaches describe non-coherent or different jamming strategies: a random, data-less pattern is incoherent noise; spreading the signal across a wider bandwidth is spread-spectrum use, which reduces power density but isn’t about coherent interference with the same data; and a single-tone jam is a simple interference at the carrier, not necessarily phase-locked to the target signal or carrying the same data.