On Fri, Aug 11, 2017 at 6:15 PM, Richard Wilbur richard.wilbur@gmail.com wrote:
Also I'd personally not use curved wriggles. HF signals travel in a straight direction. With curves they start diffracting and start bouncing cross each other and might start to radiate or echo back. But I see that the community is divided on that stance.
I also prefer 45 degree corners to the curves. Looks like they only occur in one section.
yes - i was trying to save space. ok i managed to get some 45-corner wiggles in, instead. and also got the GND separation in between the CK lines up to the via.
i'd *really* like to get this done and into test, particularly the DC3 connector test PCB (first).
ok. so wiggles1.jpg is the beginning part. track-pairs remain slightly offset, if you take the difference betweeen each pair it's nearly... 8 mm because the clock lines have to go down (3mm) then right-angle (2mm) then right (2mm) just to catch up with TX2.
so they _stay_ up to 8mm out until they get to the right end.. then they wiggle again to get match-lengthed.
BUT... it just occurred to me that on the *other* side of those ESD rclamp0524p protectors the diff-pairs are all *different lengths*.
so on the other side of the rclamp0524p components all four diff-pairs will be different lengths.
would that be sufficient, do you think, richard, to satisfy the "spread spectrum" style you were thinking of?
short lengths to the RIGHT of the rclamp0524p:
TXC: 3.11mm TX0: 1.23mm TX1: 3.23mm TX2: 1.14mm
total lengths:
TXC:57.252mm TX0:56.418mm TX1:56.398mm TX2: 56.401mm
so the signal pairs are all eever so slightly different, and they're all around 0.85mm shorter than CK.
l.
