Cable Forum - View Single Post

Sephiroth · 01-06-2011, 22:52

Look - Simples. I'm asking Masque for a more scientific basis rather than observations.

For example, DOCSIS 3, states that a single DS 256QAM channel must be in the range -13 to +17 dBmv but that the total input power must be < 33 dBmv.

Upstream ATDMA, single channel 5120 Ksyms/sec in the range 23 dBmv to 56 dBmv.

Now we all know that modems are not that tolerant on the downstream side because of the aggregated power exceeding 33 dBmv. So is it that 11 dBmv is on average true for 3 channel systems but 8.25 dBmv is true for 4 channel systems?

01-06-2011, 22:52	#23
Sephiroth Wisdom & truth Join Date: Jul 2009 Location: RG41 Services: RG41: 1Gig VOLT Rutland: Gigaclear 400/400 Posts: 12,929	Re: My Stats and PM from Virgin Look - Simples. I'm asking Masque for a more scientific basis rather than observations. For example, DOCSIS 3, states that a single DS 256QAM channel must be in the range -13 to +17 dBmv but that the total input power must be < 33 dBmv. Upstream ATDMA, single channel 5120 Ksyms/sec in the range 23 dBmv to 56 dBmv. Now we all know that modems are not that tolerant on the downstream side because of the aggregated power exceeding 33 dBmv. So is it that 11 dBmv is on average true for 3 channel systems but 8.25 dBmv is true for 4 channel systems? __________________ *Seph.* My advice is at your risk.