henrikf

7 ms·

1.
by henrikf 10mo ago
That's very impressive and I'm even more impressed if you can manage to sell tiles at that low price. PA looks suspiciously similar to SE5004L. I just needed some for my own projects but every distributor is out of stock. I wonder
2.
by henrikf 1y ago
That's Leela Zero (plays Go instead of Chess). It was good for its time (~2018) but it's quite outdated now. It also uses OpenCL instead of Cuda. I wrote a lot of that code including Winograd convolution routines. Leela Chess Zero
3.
by henrikf 1y ago
It was from JLCCNC.
4.
by henrikf 1y ago
There's not much software. PC calculates PLL register values for correct LO and source output frequencies, and transfers them to the FPGA which writes them to the hardware. FPGA accumulates the downconverted samples from the receiver A
5.
by henrikf 1y ago
I have also had issues with motivation. I had a long pause from about 2019 to 2024 where I didn't work on personal electronics projects because I didn't have enough motivation. This and last year however I have been very productiv
6.
by henrikf 1y ago
It's not on Github, but I do have schematic at the end of the blog post. vna2 is the previous version.
7.
by henrikf 1y ago
Thanks for the submission. Author here if you have any questions.
8.
by henrikf 2y ago
No, it needs to be done manually. It wasn't as tedious as it sounds though. Most of the pins are very close in delay already and there were just few traces that I had to adjust a little.
9.
by henrikf 2y ago
The FPGA manufacturer has characterized all their package pin delays. It's possible to export a csv file with internal delays of the package for each pin from the FPGA design tool. With Xilinx Vivado it's just File -> Export I&
10.
by henrikf 2y ago
I actually didn't use any expensive test equipment, only oscilloscope and multimeter. Even design and simulation software was all open source. Expensive signal analyzer or spectrum analyzer would have been useful, but they aren't
11.
by henrikf 2y ago
I built it to see if I could. I didn't have any particular use case in mind.
12.
by henrikf 2y ago
Putting ground planes on top and bottom layers isn't usually done with high speed PCBs because components are there. There would need to be a cutout on the ground plane near every chip. High speed signals really need continuous ground
13.
by henrikf 2y ago
That's a mistake in the text. You're correct that layers 2 and 5 are ground planes.
14.
Homemade 6 GHz pulse compression radar(hforsten.com)
438 points by henrikf 2y ago|116 comments
15.
by henrikf 4y ago
What's open sourced here is the design kit. Designed chips need to be sent to IHP to be manufactured. SiGe isn't also that useful for military radar applications. Compared to SiGe GaN has much greater breakdown voltage which leads
16.
by henrikf 4y ago
This is a very fast BiCMOS process with both MOSFETs and bipolar transistors. Some digital logic can be implemented with MOSFETs but since they are 130 nm it's not very competitive with smaller cutting edge CMOS processes. Bipolar tran
17.
IHP open source 130 nm BiCMOS PDK with 500 GHz fmax transistors(github.com)
53 points by henrikf 4y ago|12 comments
18.
by henrikf 5y ago
Author seems to be looking to generate a blue noise texture for image sampling. I'm not familiar with them but it seems to be blue noise which also has uniformly distributed values in time domain. Generating white noise in frequency do
19.
by henrikf 5y ago
Even worse than error message is incorrect results. I worked on the OpenCL neural net evaluation backend used in Leela Zero and lc0 Go and chess bots. We had reports of several OpenCL drivers being so broken that they gave incorrect results
20.
by henrikf 6y ago
If I understand the methodology correctly this study seems to penalize unlimited plans quite a lot. In the linked methodology pdf they specify that the price for 1 GB of data for unlimited plans is calculated by dividing by the average data
21.
by henrikf 8y ago
No need to wait for AlphaZero, you can try Leela Chess Zero today. From my experience the network without search has some blind spots, but the tree search is pretty effective in fixing them.
22.
by henrikf 9y ago
On the same PSLV C38 rocket was Aalto-1, a 3U cubesat that has electrostatic plasmabrake that is a different de-orbiting experiment. It uses 100 m long hair thin wire that is electrically charged and brakes the satellite by interaction with
23.
by henrikf 9y ago
That's the rumours I was referencing. Deepmind hasn't confirmed anything yet.
24.
by henrikf 9y ago
Deepmind released three AlphaGo vs. AlphaGo matches last year and around the new year AlphaGo played 60 games against top professionals online winning all of them. There have been rumours about AlphaGo vs. Ke Jie (No. 1 Go player), but noth