--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Tue, Dec 12, 2017 at 2:54 PM, mike.valk@gmail.com mike.valk@gmail.com wrote:
We'll I'm not convinced on the reflections in inter pair matching. But indeed my "linear" might not be the best and results in unequal impedance transitions and thus in signal degradation. But you can stil do gradual corners. See the "transitioned" attachment.
yes. the issue i have with the 45-degree thing is that it has to be staggered (you can't make the transitions on *exactly* the same X-distance along the axis because the pairs, during the 45 degree turn, would actually come *too close* by a factor of pow(2,0.5) * 5mil.
a non-45-degree variant - exactly as you draw - would not have that same problem. *but*.... at the same time, 8 steps would not be anything like enough, because of the risk of inaccuracies in the distance between the tracks, perhaps going to 4.95mil separation at the exact point where each track turns. all a pain.
and that's why i said that 100s of such steps would be needed... which i'm not going to do right now, as i would need the actual formulae from the 1956 paper as opposed to richard's hand-calculated 8 steps.
But without a, 3d, simulation or a real world test this is all very theoretical.
the theory - which has had quite some time to mature and be demonstrated to be accurate both in complex electrical simulations (papers doing this were referenced on arxiv.org in the original message that richard sent a few months back) and the real world - has matured over the past 60 years and that's why i'm trusting richard's assessment.
l.