What is true about the effect of a high Jammer-to-Signal Ratio (JSR) on reception?

• A. JSR has no effect on signal quality.
• B. A higher JSR indicates greater potential degradation of reception.
• C. JSR only applies to baseband signals.
• D. JSR is the ratio of jammer energy to noise floor.

Answer: (B)

The key idea is that how strong the jammer is compared to the wanted signal determines how much interference the receiver has to deal with. A high Jammer-to-Signal Ratio means the jammer’s energy dominates the received signal, so the interference level rises relative to the desired signal. That lowers the signal-to-interference ratio, making demodulation harder and increasing error rates, possible loss of lock, and receiver desensing.

So a larger JSR naturally leads to greater potential degradation of reception. It isn’t correct to say JSR has no effect, nor that it only applies to baseband, or that it’s simply the jammer-to-noise-floor ratio, since the critical factor is the jammer relative to the signal power at the receiver.