Thanks guys for trying to explain, and thanks Jeff, I think I understand. First question is, it says in the explanation on the website you can only have 15 bits per tone, not 16, which is correct?
Also, how do you know that 3dB equates to one bit?
Also, 15*4Kbs = 60Kbps per tone. According to the website, ADSL has 223 downstream tones. However, 223*60Kbps = 13,380Mb/s which is too high for ADSL, can you explain this to me?
Second, how do you know how many bits are allocated per tone based on SNR?
I understand now how Target SNR affects speed, but how does having a lower target SNR decrease reliability?
Finally, SNR is obviously defined by the line, and what things are around it. So lets say your SNR is 50dB, and your target SNR is 3dB, how does the line synchronise with a selected SNR, because SNR is defined by the line, and things around it?
@ HP Sauce - I'm actually an apprentice telecoms engineer, and have covered QAM in a basic format, so know what it is. However, can I ask, how is QAM doing 4,000 symbols per second? What exactly does this mean? It's just ADSL I haven't done much of because I work for a major business supplier, who doesn't do residential, meaning ADSL isn't one of our bigger prodcuts. Hence why I'm trying to learn myself!