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It is possible for the signal to be below the background noise. For example, GPS works this way. Sonars on submarines do the same thing, they send out a noise-l
by pps43 8y ago
It is possible for the signal to be below the background noise. For example, GPS works this way. Sonars on submarines do the same thing, they send out a noise-like signal that can be detected only if you know what to correlate it with. There's always some noise to hide the signal in.
- garmaine 8y agoThis isn’t true. If the signal was below the noise threshold, and no mechanism provided for detecting noise separately (as twisted pair provides, for example) it would be literally impossible to separate signal from noise. That’s what the noise threshold means. GPS is not below the level of background noise. Not is sonar.