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1
gEDA / Re: PCB-RND
« Last post by saike on Today at 06:00:08 AM »
Good, I haven't checked in on PCB-RND for a while. I hope a few more developers come on board now.
2
Buy/Sell/Wanted / Re: I need a equivalent of an integrated circuit.
« Last post by 741 on Today at 05:55:03 AM »
Hi

What is the application?

Are you certain about the part number?

Is this a replacement - in which case, can you post a photo of the chip?
4
General Chat / Re: Which scope for this i need ?
« Last post by hans on Today at 05:51:25 AM »
Benchmark of components: look at the right reviews.
E.g. https://uk.hardware.info/reviews/7652/9/18-x299-motherboards-review-battle-for-first-benchmarks-cpu

I don't think you'll often find performance comparisons between a whole range of boards for a particular platform. Some of these benchmarks are synthetics, some are real-world like x264 encoding. What is applicable? Depends on your application, and if you want to make any judgements yourself, you better get to know it.
As you can see, practically any board from "bottom of the range" up to "top end" performs the same. There are some outliers, but it almost goes without saying that these boards have OC profiles applied "out of the box", mostly being enthusiast grade level boards. This was especially a huge shitstorm when the i7 8700K coffee lake CPU's landed, and some reviewers with non-Asus boards got a Cinebench score in the 1300 region, and some others with Asus boards got 1500+, while a few reviewers with Asus boards got 1300 points again.
Reason: there was a Asus-specific "enhanced multi-core experience" setting enabled by default, which allowed for higher turbo clocks for longer, as long as cooling permits. Some reviewers turned this off, some others didn't, some others didn't have Asus boards.. so they didn't have this feature.
This also somewhat concludes that benchmarking is hard, it's easy to get the results you want, and not the ones you should get.

But in most cases, stock settings are applied: stock clocks, stock memory speeds, all the advertised speeds by Intel ARK. You can buy 4000MHz RAM, but it will probably run at the "validated" 2333 or 2666MHz. Unless you manually go in there and load a XMP profile or put it up higher. Similarly, you could go manually into your BIOS and try to OC your system to gain more performance. But honestly anyone that is targetting a workstation application would leave this kind of stuff out of their damn mind.

If you need to figure out what combination of parts works best for your application, then motherboard reviews can be pretty useless. They are basically a non-factor, unless you need a very specific I/O benchmark, like USB3.0 transfer speeds..
Look up a CPU review and figure out how your application scales with memory bandwidth, CPU single-core and multi-core performance, and how well these demands fit in the offerings of AMD and Intel.

Puget systems also performs a lot of these benchmarking, alot of it is available to the open public in their publications. Unfortunately, a lot of focus is on media creation though, as it tends to have alot of benefit from GPU acceleration if done right.
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from PSPL app note  AN3045C:

They use their pulse sharpener to mod the 18 GHz 54754A TDR
to 50 GHz, using a non-TDR 50 GHz 54752A  scope plugin. That
means that they must re-implement the coupling to the DUT.

Picosecond Pulse Labs has been bought by TEK, but the app note
is still on the net. The app note is about comparing different TDRs.

The 54750 can use convolution to calculate away its own risetime.

regards, Gerhard

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General Chat / Re: Alien or Driftrock...
« Last post by apelly on Today at 05:39:50 AM »
7
The real hand crimper, which I have used but did not own is just a little expensive.
TOOL HAND CRIMPER 28-32AWG SIDE, at Digikey Unit Price $1,057.68 455-1236-ND
And is also hard to use.
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General Chat / Brymen 235 battery life?
« Last post by Russ on Today at 05:36:01 AM »
Hello

   How much battery life (approximately) are you getting from the two AAA cells? I had about three hours on a set of Eneloops, and the battery icon flickered slightly. I immediately pulled them, and got a reading of 1.275v from them. I then just dropped in a fresh set. I’m not really complaining, just curious.

Thanks
Russ
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I agree that OLED could and should be amazing if the technology evolved a little further. Unfortunately, we're still stuck in the period that the technology is expensive and the longevity isn't anywhere near what it should be.
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Rotate the crystal 90 degrees so you can place it closer to the 2 pins it connects to. The example schematic in the CH340G datasheet shows 22pF load capacitors like you have so when you choose a crystal make sure you find one that has that, or close to it, load capacitance specified, something like the ECS-120-20-5PX-TR

What layout program are you using, if it's something I have installed on one of my machines I can show you what I think would yield a better layout.
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