It is not often that you get a negative SNR and maintain the sync, but mine has been dipping below zero and just climbing back up above for a while all day long. :thumb:
On Adsl2+ it has a nominal 3dB margin and has been hanging in there since Christmas.
(http://www.clwydpark.co.uk/snr.jpg)
The modem must be working right at its limits to maintain the sync.
The lowest mine ever went to was -0.7 ... it would often sit down at -0.1 or -0.2 for quite long periods (tens of minutes).
It does show how good the front end of the 2700 actually is.
It's why we love them. :)
If I'm thinking correctly, -0.7dB would mean the noise is actually more significant than the signal by a factor of ~1.2. Something like that anyway.
Quote from: esh on Mar 15, 2011, 11:30:23
If I'm thinking correctly, -0.7dB would mean the noise is actually more significant than the signal by a factor of ~1.2. Something like that anyway.
Yes - but remember that the noise is measured and averaged across the band as is the power of the signal. There could be a very noisy part of the spectrum which creates that effect - but it still shows how well the 2700 copes with high noise levels.
There are comms systems where the signal can be 10 or 20 dB below the noise floor - but by careful use of multiple antennas and electronic beam steering (introducing nano delays) it is possible to bring the signal up above the noise.