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This is a "truthy" statement that sounds right but is, in fact, false. Radio systems have an easily measurable SNR, but the noise cannot be eliminated.
by sobellian 2y ago
This is a "truthy" statement that sounds right but is, in fact, false. Radio systems have an easily measurable SNR, but the noise cannot be eliminated.
- vasco 2y agoYou can measure is from outside the system itself if you know the original signal. Of course its possible to measure the noise externally if you know what was transmitted.
- sobellian 2y agoAFAIK this is incorrect. There exist modulation schemes where the received signal power is evident. For Wifi the signal is usually > 10-100x the noise floor and it is modulated with phase-shift keying. So there is no technical problem with seeing a noise floor, then receiving a much larger signal with constant envelope and calculating an SNR. ETA: Just to sharpen the point, this is clearest when considering digital noise and error correction. It is easier for error correction codes to indicate a corrupted message than it is to provide the correct message.