Timeline for Multiple level signal transmission
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Nov 8, 2012 at 21:14 | comment | added | JonSlaughter | Basically you are stating theoretical facts. It is obvious that adding multiple voltage levels per conductor will decrease the noise immunity, which is why I suggested pre-amplifying them to a larger voltage level to keep the same interlevel voltage margins. So, again, the question is not if but how much and that takes either a lot of math or real world data... | |
| Nov 8, 2012 at 21:12 | comment | added | JonSlaughter | I can't argue with you on the subject. Obviously there is an effect but the issue is how much. Since ethernet does not seriously suffer from these issues AFAIK, it seems to me like it is not a big deal. I must assume that for Cat5+ the issue is not a problem(in general). The question then remains if the multiple voltages per conductor increase this problem. I do not know and you have no proved this in any way(no offense, just that you haven't given any logic or evidence to suggest it will be an issue when going from single to multiple voltage levels). | |
| Nov 8, 2012 at 21:08 | comment | added | Olin Lathrop | @JonS: There are lots of ways differential mode noise can show up at the receiver. Assuming all noise is external and common mode is not good since that's simply not how real systems work. Much of the external noise will be common mode, but some not, and even some of the common mode noise will appear as differential noise at the receiver. You are going to have differential noise. There will be a finite signal to noise ratio, and that together with the bandwidth will limit the total data transfer rate. You can't cheat basic physics. | |
| Nov 8, 2012 at 20:59 | comment | added | JonSlaughter | Olin, the differential noise will exist on normal single bit methods. The larger voltage transitions may increase differential noise, maybe to an unacceptable level BUT this is why I'm asking questions. Every method has it's drawbacks. I do not think differential mode noise is one of them in this specific case but it is possible. | |
| Nov 8, 2012 at 20:52 | history | answered | Olin Lathrop | CC BY-SA 3.0 |