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I have read the sampling rate should be 5x the MHZ.

The only important signal parameter is the transition time, since that determines the signal's bandwidth. FFI see https://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/

In order to reconstruct the signal from the samples, there need to be at least two samples per period, e.g. a 10MHz signal needs at least 20MS/s. In practical scopes there needs to be at least 2.5 samples per period, i.e. 25MS/s for a 10MHz signal. For convenience, many scopes have much higher sampling rates (e.g. 10 samples per period) - but that does not change the signal's bandwidth-transition time relationship.
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Microcontrollers / Re: Memory model for Microcontrollers
« Last post by Kittu20 on Yesterday at 11:55:18 pm »
I think that the C memory layout sections like .text, .data, .bss, .heap, .stack depend on the type of microcontroller and compiler. We cannot view these memory sections for 8051 and PIC microcontrollers because they do not support them, whereas we can view these sections using STM32CubeMX and STM family
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Repair / Re: Tek FG502 fails at high frequency end of dial - help needed!
« Last post by gcwills on Yesterday at 11:54:09 pm »
To add to the story of my FG502 issues, I came across this reference to a similar issue with a FG502 on the TekScopes group:
https://groups.io/g/TekScopes/message/180842?p=%2C%2C%2C20%2C0%2C0%2C0%3A%3Acreated%2C1%2CFG502+doesn%27t+start+at+some+specific+settings%2C20%2C2%2C0%2C81500580

Of interest to me was the comment "Perhaps some of the transistor gains decreased over time and now positive feedback coming back through C247 is not strong enough."
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Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier
« Last post by RoGeorge on Yesterday at 11:52:37 pm »
I was wondering if using a poly-phase mixer could improve a LIA, because of the reduced noise factor specific to poly phase mixers.  :)

Should be easy to double the frequency of the reference signal (in order to divide by 2 again, while producing precise quadrature I/Q of the same frequency as the reference) then to use the I/Q to drive the switches of the poly-phase mixer.



Side note now that the quadrature of the reference signal was mentioned, the schematic of the kit in the first post is not exactly a LIA, in my opinion that schematic is rather a synchronous detector.  What I'm trying to say is, a LIA has to have 2 mixers, one for each of the I/Q components of the quadrature reference, in order to extract both the amplitude and the phase of the fain signal.

It's 2:30 AM here and didn't check against the datasheets, but the schematic of the kit seems to have only a single analog multiplier, and no I/Q splitting of the reference signal.  Though, sometimes the architecture with 2 mixers is called a two-phase lock-in amplifier.  Well, I've always thought a LIA should be able to tell both the phase and the amplitude of the small signal.  If it doesn't have quadrature reference and 2 multipliers, I think of it as a synchronous detector (and I don't call it a LIA).  But I'm not sure if I use the proper naming.
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Microcontrollers / Re: Memory model for Microcontrollers
« Last post by tellurium on Yesterday at 11:42:14 pm »
I think this AI bot should just be banned
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Jobs / Re: Contract Job - EEVblog: Making Shorts/Reels
« Last post by SiliconWizard on Yesterday at 11:39:51 pm »
A profesisonal short company sent me these demos as an example of what they can do. What do you think?
Yes there are spelling errors, and yes they are a tad annoying.
Are they for hearing impared people? What is the deal with the Karaoke dubbing?

I hate those shorts, but these demos are pretty much the epitome of what shorts are supposed to be like. 99% of shorts are like this, with the animated subtitles and loud voice (and often music.)

Shorts are primarily targeted at a young audience, binge-watching them on their mobile phones and with the attention span of a goldfish.

YT creators are pressured into making those, and creators offering no shorts will see YT "algorithms" lower the exposition of their other, conventional videos. Which is why most Youtubers feel compelled to make them.
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General Technical Chat / Re: Is LinkedIn worth keeping?
« Last post by dcbrown73 on Yesterday at 11:37:05 pm »
I'm a c-level IT executive.  LinkedIn is only good for providing a way people selling something to find you.

Meaning I haven't found anything of value that LinkedIn provides.
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Open Source Hardware / Re: ESP32 Ethernet, Wi-Fi & Serial Gateway
« Last post by tooki on Yesterday at 11:33:13 pm »

You are right about the certification, but I personally don't prefer to use modules instead of bare MCUs. Even I used it, I would need to get a certification for the whole product.
Huh? I thought the whole point of using the pre-certified modules is to avoid having to get your own certification for the product.

And there is another purpose. After I decided to do an open source design, I wanted to contribute more by not using a module and by doing the PCB antenna design from scratch for this board. ESP32 modules' PCB antennas are not that good, and I thought there was a room for an improvement.
Devil’s advocate: how many others will avoid your design precisely because it’s not certified? And why not just use an ESP32 module with antenna connector (instead of PCB antenna) if one needs better wireless performance? (I use those when I have an all-metal enclosure, so I can attach an external antenna.)
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Other Equipment & Products / Re: Which 3M static shielded bag
« Last post by tooki on Yesterday at 11:28:12 pm »
If you want responses, provide some “meaty” question to respond to. The only thing you mention is “for 3.5” HDD, resealable, ideally 3M”. You don’t mention any other requirements, nor the reason you’re unable to select one yourself. What’s holding you up?
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Repair / Re: Advice on aperture repair on camera lens
« Last post by lukashts on Yesterday at 11:25:40 pm »
It isn't software related. The aperture motor doesn't have the oomph to close the aperture for a split second in photo mode but in video mode the aperture increases in small steps so there's less resistance.
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