@th@whitequark It actually could handle a lot more noise than that if you build a receiver designed to oversample the signal and pre-filter the noise. Frequency selective filtering and non-linear filtering could probably pull a UART signal out of negative SNR territory. You'd want to add some latency to filter and process whole words at a time. Nobody does this in practice, but it's possible.
@th @whitequark It actually could handle a lot more noise than that if you build a receiver designed to oversample the signal and pre-filter the noise. Frequency selective filtering and non-linear filtering could probably pull a UART signal out of negative SNR territory. You'd want to add some latency to filter and process whole words at a time. Nobody does this in practice, but it's possible.