[Arm-netbook] HDMI High-Frequency Layout: Recommendations
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Fri Aug 11 07:04:58 BST 2017
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Fri, Aug 11, 2017 at 2:56 AM, Andrew Bolin
<fivepointpalmexplodingheart at 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.
>> mmmmm.... *stress*! anyone else feel the curves are "Bad"?
> No. You've followed a bunch of very good advice about length matching,
> impedance etc.
> It looks like you've generally kept the pairs parallel through the curves,
> which is great.
> If you have an easy option in your software to switch from 45 degree
> corners to smooth curves, I would do it - if there's not, don't worry.
i did those by hand using the "accordian" feature
>>> If tight for space you can use 90% corners with a chamfered outer
>>> edge. I suppose the chamfer acts like a mirror.
> The chamfer is there for impedance reasons, it's not a mirror, and note
> that a curve is preferred.
> You also run the risk of manufacturing problems by doing the chamfer -
> you're already at the minimum trace width, right?
> As you've previously said, the old layout was further away from best
> practices, and *it worked*.
but it was done by someone else and it didn't use curves.
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