Here is the .bin extracted from my Fnirsi DPOS350P, but I think it's the simplest step. Much more complicated is the reverse engineering with the firmware.
did anyone made board circuits?
Yes. (Design and assembly of printed circuit boards.)
Here is the .bin extracted from my Fnirsi DPOS350P, but I think it's the simplest step. Much more complicated is the reverse engineering with the firmware.
Can you post a screenshot of a 20MHz square wave? How does this 350MHz scope handle square waves?
I don't have such generator that could handle 20MHz square wave.
Two screenshots: with a probe and without a probe and terminated at the scope with a 50 ohm pass-thru.
I don't have such generator that could handle 20MHz square wave.
Can't you use the built-in generator?
Something intriguing is bandpass display out to 50MHz. That requires a tracking generator. They must be using the built-in generator.
Can't you use the built-in generator?
Something intriguing is bandpass display out to 50MHz. That requires a tracking generator. They must be using the built-in generator.
The built-in generator performs poorly with square waves, supporting only up to 10 MHz. In my opinion, for accurate measurements, the generator should handle at least 25 MHz so that the square wave edges don’t look smoothed at 20MHz.
I don't have such generator that could handle 20MHz square wave.
Can't you use the built-in generator?
Something intriguing is bandpass display out to 50MHz. That requires a tracking generator. They must be using the built-in generator.
I think the major problem with most of the signal generators out there is that they won't generate enough harmonics for displaying a decent square wave. It doesn't matter what brand it is. You can easily check this by doing an fft analysis. When the frequency is close to the max square wave frequency it generates 2 or 3 good harmonics max and that's not enough for a good representation of a square wave. That's one of the reasons why most tests done on oscilloscopes fail to display a square wave at higher frequencies.
Yet another tiktok-style promotional video from Fnirsi in portrait mode 
https://fb.watch/z0Ypf8Sl9t/
Even if it isn't the greatest oscilloscope in the world it might be the cheap Bode Plot machine that everybody's always searching for.
YES!Back when dinosaurs with pocket protector roamed the Earth, I remember what a nightmare it was to do Bode Plots. I've done them with paper and pencil, lacking the resources to buy a suitable tracking generator.
And it can do that through 50MHz!
I would think that might make it popular among ham radio enthusiasts, as it covers the whole HF spectrum. IF stages, crystal filters, even SDRs are begging for something like this.
We know how wide it is (or at least, specified). Too bad it's probably only about 20db (8 bits) deep.
As to the FRA:
Fix the phase problem and add more log cycles for wider sweep ... PLEASE.
This could bolster sales and help the company's reputation.
As to the FRA:
Fix the phase problem and add more log cycles for wider sweep ... PLEASE.
This could bolster sales and help the company's reputation.
I just want to see if they will release a dedicated FRA/spectrum analyzer for 80 bucks like the creator mentioned some posts back. If they do it, maybe that time the phase plot is correct.
Here is an example. The Fnirsi Bode plot is decent, but the phase is inverted and the log cycles are screwy.
Fnirsi is an enigma. They seem to put in a good effort and then poop out near the finish line. Why not spend a little more time and finish what they started
I've read so much negative feedback about this oscilloscope. If I didn't already have one and actively use it, I wouldn't have bought it.
But I definitely like it. Its capabilities far outweigh the price. The only change I had to make was installing good 1 GHz probes, and the picture and accuracy improved significantly. Phase shifts were reduced and became insignificant.
There are still a few drawbacks, for example, that it can freeze or turn off. Or that it doesn't show measurements at low frequencies. But these aren't that significant. I hope they fix this with firmware. The heading measurements still work at all frequencies.
I definitely won't be upgrading to another one in the next year.
1 GHz probes
What probes did you pick for it?
I don't think there is anyplace in the world that allows people to spread false information…
[/quote]
In the US, the Supreme Court ruled that advertising does not have to be truthfu, and can indeed indulge in blatant falsehood. And FOX News argued in their defence (that they ultimately lost 3/4 of a billion on) that they weren't really "news", but rather, "entertainment".
And Convicted Felon Cat Meat can hardly get through a tweet — let alone a 70-minute lecture to the UN — without lying.
I'm afraid we're in a truth-free zone right now.
but not the scopes, they are too expensive. They should cut the price of dpos350p to around 70 bucks, that's a fair price for the quality of the unfinished, incorrect functions, and enough for nice graphics and basic operation.
Could you name any scope that has similar form-factor? I mean tablet-like scope with 6-10inch touch screen?
Micsig VATO2004.
And you can attach a tablet as big as you want
That isn't a scope. It's a black box.
I have a Tek TDS 724D (500MHz, 2Gs) that I've converted to a 784 (1GHz, 2Gs) for when I want to have one arm longer than the other and don't mind managing cables.
I want something that I can carry around without a bunch of cabling. I very specifically want something that does not require a separate tablet or phone.
Since you got a dpos350p try triggering an AM sine wave signal carrier 10MHz, mod sine wave 300Hz at 80%, then you see what you bought for 200 bucks.
You keep saying this, and yet, @BillyO managed to post good-looking screenshots of that signal.
To me, that makes it sound like a cockpit problem. Just sayin'.
If you just need a few quick checks, there is a smaller pocket scope for that.
Ah, you must be under 40!
My eyes can't even look at a smart phone, let alone a scope with a screen that is considerably smaller than a smart phone.
I can put up with a lot of issues for a 1024 pixel screen.
If I can't see all the wonderful goodness on a device with a 400x256 screen, what good is it? I want a portable device that I don't have to carry around #3 reading glasses for.
You can't really check a TCXO frequency with only two digits after the dot or a crystal resonance frequency. You can only guess or do the math manually.
Correct.
You're trying to check a platinum precision metre measure with your wife's sewing tape.
A good TCXO can cost as much as that scope. A GPS-referenced one, ten or more times as much.
Yeah, I don't understand how that gradually changed: First, Chinese device manufacturers got users used to the idea that a measuring instrument should be affordable and cheap. Then they got them used to the idea that an oscilloscope should do everything well: 3-in-1, make coffee, and even clean the apartment 
Then they pushed the idea that these devices can also be accurate. That last point I don’t believe, because professional equipment must go through calibration (I don't mean that magic button on the screen) and certification, and certainly shouldn’t be measured "on the fly" with some unmatched probes.
Cheap, functional, accurate: pick two.
