--- crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Tue, Dec 5, 2017 at 12:41 PM, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
On Tue, Dec 5, 2017 at 12:30 AM, Richard Wilbur richard.wilbur@gmail.com wrote:
- Reflections are more troublesome the further you get from the
signal source. Close to the source the reflection arrives at the source during the signal rise time and can be overcome by the line driver.
Deviations from path in due NorthEast direction (+ signifies change in the NorthWest direction, - signifies change in the SouthEast direction, units in mil) <step> <Northern keepout> <TX1> <TX0> <TXC> <Southern keepout> 0 0 0 0 0 0 1 -1 1 2 3 4 2 -1 1 2 3 4 3 -1 1 2 3 4 4 -2 2 4 6 8 5 -2 2 4 6 8 6 -1 1 2 3 4 7 -1 1 2 3 4 8 -1 1 2 3 4
okaay so the idea is, just after the long straight you make a series of very tiny corrections by bringing each of the tracks inwards - closer together - so that when you get to the point where you *have* to be 5-7mil apart you're already neeearrrrly that far apart *anyway* so it's not so bad.
ok :) that's perfectly doable.
so, a quick check: it's easier, due to the VIAs (i am *not* moving them!! certainly not the diff-pairs!) to keep TX1 exactly where it is, and move TX2, TX0 and TXC all inwards. i'll also move the last change from N to NE that goes round the GND via a bit closer in.
question: does it *really matter* that the tapering occurs after the 45 degree group turn or is it ok to simply... ok picture 1 or picture 2? :)
thoughts appreciated
