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General Technical Chat / Re: Admit your Brain lock
« Last post by Sal Ammoniac on Today at 03:02:11 pm »Why there's something rather than nothing.
coastal areas and ports are sulfur emission controlled areas, so there they run bunker A which is basically diesel
floating relative to mains
You can do the same with multiple power supplies too
But why it picked up FM signals which lies in 101.1 Mhz? i have never seen something like that before... also the picked up signal was pretty clear... i forgot to take a video of it happening also it only worked at that timeThe op-amp doesn't need to oscillate at 101MHz to pick up an FM station.
What's happening is there's a tuned circuit somewhere, which is resonating at 101MHz. This is being rectified by a PN (diode) junction in your circuit and amplified by the op-amp.
It's an amplified crystal radio. Normally crystal radios are known for AM (Amplitude Modulation) but they can work with FM (Frequency Modulation). In your case, the tuned circuit will have a sharp peak, so the amplitude of the resonance will change, as the frequency of the signal changes, resulting in amplitude modulation, which is being rectified.
Here's an article about FM crystal radio, if you're interested.
https://electronbunker.ca/eb/FMCrystalSet.html
Going back to your problem. It's probably lack of decoupling and poor layout. The low level signals should use screened, preferably twisted pairs. Also try adding ferrite beads to the outputs of the power supplies.
The schematic of your output stage also isn't clear to me. Please use proper symbols, rather than just boxes.
kreyren on 29 March 20, 2024QuoteDiTBho on March 20, 2024
Just checked, the pinetab2 uses the Rockchip RK3566 SoC
Afaik the reason why OLIMEX didn't provide the RK3399 and RK3566 is that they were very unreliable software-wise (afaik they release the chip and then rely on the community to mainline them while not providing sufficient amount of documentation?) and tsvetan not wanting to support that as the resulting mainline is often very problematic and takes long time to get implemented in a way that is acceptable in industrial settings (OLIMEX's main focus)
For me in terms of arm architecture only use Cortex A7/53/55 and consider everything else garbage due to the CPU vulnerabilities, but i plan on supporting all chips as long as the required docs to make boards for these are available or unless someone wants to do the adventure of reverse-engineering them and contributing that (that's what the SOM management is meant to be for)