New handheld/desktop DSO+DMM, Fnirsi 2D15P, 100MHz/500MSpS (september 2025)

[ataradov]

I tried it. I see no obvious visible differences. The weird scope behavior with flickering trace is still there.

[aristak]

BillyO It seems like this
- Added language selection interface on first power-on
- Fixed multimeter buzzer sounding when measuring AC mains
- Shortened power-on press duration
- Multimeter capacitance measurement no longer clears the waveform
- Swapped functions of the two knobs
- Fixed pop-up issue on CH1 when pressing the knob
- Fixed low-frequency trigger failure bug
- Fixed inaccurate low-frequency duty cycle measurement bug
- Corrected half-wave and full-wave signals being reversed in the signal generator
Modify message

[BillyO]

Thanks,

As noted by ataradov, that is the list for an earlier version.  Specifically v1.2.0.6.

[ataradov]

The only thing that changed in this version is:

V2.6.0.7 260320
- Fixed a bug where the cursor did not follow the probe ratio.

I ran though the menus and basic operations, and visually I see no other changes that I can spot. I have not used cursors in the old version, so I can't say what this bug was.

[ataradov]

Is this some gaslighting campaign? Why is everyone keep reposing the same list of changes from v1.2.0.6?

v2.6.0.7 does not fix any of this. All of this was fixed a long time ago, before EEVBlog thread even existed.

[dalhend]

Yes... I deleted my post after noticing the "2" lists I found online are very similar.

[BillyO]

One thing I can say for this little scope meter is that it is the first FNIRSI that I know of that has standard spacing on the DMM sockets.

Way to go FNIRSI!  Keep it up! 

[BillyO]

BW sweep from 10MHz to 110MHz.

This was direct from the generator through a 50 ohms pass-through load.

You can see that the amplitude rises.  I'm wondering if this is done to make up for the probes?  I'll re-do the sweep when I get a chance using one of the probes, but as it stands +28% in amplitude is only about 2.2dB.  From my perspective, that's not horrible.  It's not great, but it's not horrible.  We'll make a final conclusion when I do the probe sweep.

At 110MHz it begins too lose it's mind.  It's running up against the sampling rate.

First image is 10MHz to 60MHz, 2nd image is 70MHz to 110MHz.

[BillyO]

Okay, I did the sweep using the probes instead of direct connection.  Exactly the same results.

[BillyO]

Been playing around with this again and I'm really liking it.  The UI is really nice and intuitive.  It's just a nice little scope to use and head and shoulder above all the other mini-scopes I've tried.

I know they did not publish any accuracy specs on it, so I did some testing on that too and it looks as though it's well within 3 counts on just about everything.
I hear those yellow meters are supposed to be pretty good. 

In the last shot, that Siglent generator is referenced to a GPSDO, so when it says it's putting out 1,000,000 cps, that's exactly what it's putting out.  The Fnirsi is showing 1.0000 MHz.

[Caatz]

I got mine today, I did not notice the weird "afterglow" effect that looks like an old CRT oscilloscope. Then I saw the 2.6.0.7 update on the Fnirsi website, and proceeded to update it. Then I got hit with the issue.

Apparently my scope had FW version 1.4.0.7 which is not in the Fnirsi Download page. So I'm unable to return to my original FW, in which I did not spot the issue. I didn't spend to much time playing with it before the update so I cannot say for sure the issue wasn't there, but I did not notice it, after the update it was very noticeable.   

[ataradov]

It is weird, since it would be the first time this version is reported. I think all versions have this issue, since it is by design. It is more likely that you just did not pay attention. You can try  v1.2.0.6 to see if the issue is there.

[sizziff]

It is weird, since it would be the first time this version is reported. I think all versions have this issue, since it is by design. It is more likely that you just did not pay attention. You can try  v1.2.0.6 to see if the issue is there.

With version v1.2.0.6, the oscilloscope started up for me, but the signal was not displayed.

[Caatz]

I'm 100% positive on the firmware version (1.4.0.7). Saddly I did not take a photo, as I thought it was not important. Not 100% positive on the "afterglow" issue. Nevertheless, me and a friend, both, did not notice this effect in the beggining, but inmediately noticed and researched it after the update. I tried all available FW versions, 1.2.0.6, 2.0.0.7, 2.6.0.7... All of them had the same issue. 1.2.0.6 just had thinner traces and smaller font 

[ataradov]

I expect all versions of the firmware would have this. "Afterglow" is not a bug, it is an explicitly documented feature. It is stupid, but this is what they want to do apparently.

[BillyO]

I don't mind it so much.  Yes, it's stupid, but it does not hamper the use of the scope.

[sizziff]

The biggest problem with this oscilloscope is how it displays fast signals.

In the screenshot, there is a square wave from the same generator. The frequency is decreased by just 100 kHz, from 4.2 MHz to 4.1 MHz, and the edge goes from a reasonable 5–6 ns to 25–30 ns!!!! What? Why? How does this even happen?

So, if you plan to use this oscilloscope with signals whose transition time may be shorter than 30 ns, I absolutely do not recommend it.

More details in this video:

[BillyO]

Confirmed.

Have you reported thi to FNIRSI?

[sizziff]

Confirmed.

Have you reported thi to FNIRSI?

Yes, I reported it several times. The last time, about a month and a half ago, I even got a polite reply basically saying: “This time your information has definitely reached us, and we’ll take action.”
But no fix has appeared so far. The recently released version 2.6.0.7 still doesn’t solve the issue.

[BillyO]

I'll put in a report too.

I'd request everybody that has one of these, put in a report with a couple of screenshots.

[BillyO]

In playing around with this issue, the rise time changes between 4.20 and 4.19MHz.  Everything from 4.20MHz and above has a rise time of 7.5ns (the limit of the sig. gen. I used.  The limit of the scope seems to be around 2.6ns), everything from 4.19MHz and below is suddenly increased to 26ns minimum.

Is it possible this may be built into the hardware?  It's almost like something gets switched at that point.

[sizziff]

In playing around with this issue, the rise time changes between 4.20 and 4.19MHz.  Everything from 4.20MHz and above has a rise time of 7.5ns (the limit of the sig. gen. I used.  The limit of the scope seems to be around 2.6ns), everything from 4.19MHz and below is suddenly increased to 26ns minimum.

Is it possible this may be built into the hardware?  It's almost like something gets switched at that point.

Let me start by saying that this is only a hypothesis.

In my opinion, the problem does not look like a limitation of the analog bandwidth. If it were simply caused by a low-pass filter, the waveform would look more like the example in screenshot #1 — the edges would become smoother, but the behavior would change gradually rather than abruptly.

With the 2D15P, the situation looks different. Above about 4.2 MHz the waveform is displayed quite reasonably, but when the frequency is reduced by only 100 kHz to 4.1 MHz, the edge shape changes dramatically and becomes suspiciously symmetrical. In addition, there are clear signs of heavy interpolation — the characteristic "waves" and "steps" on the edge.

Because of this, I suspect that below a certain frequency threshold the oscilloscope switches to a different digital processing mode (decimation, interpolation, sampling mode, etc.) rather than simply reaching the limits of the analog front-end. In my opinion, this would better explain such a dramatic change in waveform shape caused by only a 100 kHz change in frequency.

[ataradov]

Fnirsi are known for fudging the waveforms. On some of their handlehld models when they detect input frequency that is too high, they just generate their own sine. They assume that bandwidth limit will not let anything but sine though, so might as well make it look pretty. But it relies on a frequency threshold, so misdirected frequency sometimes results in strange behavior.

[BillyO]

I don't think this is an insertional "fudge" as it's working the wrong way.  The waveform is a truer representation over the 4.2MHz.  I really believe there is something erroneous going on here.  They are not turning things into a sine wave and the rise time above 4.2MHz is far more accurate than the rise time below 4.19MHz.


@sizziff: The transition actually happens over about 10kHz.   From 4.19MHz to 4.2MHz, and it happens transitionally.  By that I mean at intermediate frequencies it switches back and forth between the two slopes.  Also, I think a lot of the "ringing" you are seeing is because you are not terminating the cable from your generator with 50 ohms at the scope.  Look at the images I've attached.  Using a 50 ohm pass-through the "ringing" you see is gone.

[sizziff]

Fnirsi are known for fudging the waveforms. On some of their handlehld models when they detect input frequency that is too high, they just generate their own sine. They assume that bandwidth limit will not let anything but sine though, so might as well make it look pretty. But it relies on a frequency threshold, so misdirected frequency sometimes results in strange behavior.

The “sine wave” that is often seen at the upper frequency limit is usually the result of sinc interpolation. Almost all digital oscilloscopes that use sinc interpolation do this. Sinc interpolation itself is not the problem.

The problem with cheap oscilloscopes like FNIRSI or Zeeweii is different: they often leave only 2–3 real samples per period, and then use sinc interpolation to draw a nice-looking waveform. At the same time, they still advertise that frequency as the working bandwidth of the instrument. In my opinion, for a more or less honest display of the waveform shape, the usable bandwidth should be closer to Fs/4...Fs/5, not Fs/2.

FNIRSI artifacts at maximum frequencies do not surprise me much. Everything is expected there: too few real samples, too much dependence on interpolation, plus not the best implementation of the software and rendering.

But with the 2D15P, something else bothers me. At frequencies above about 4.2 MHz, it displays the signal relatively adequately, but when the frequency is reduced to only 4.1 MHz, the waveform suddenly becomes worse. So the problem does not appear at the upper frequency limit of the instrument, where it could still be explained by a lack of samples and sinc interpolation, but at a much lower frequency, where the oscilloscope should behave quite adequately. From a hardware point of view, the 2D15P has everything needed for that: a 500 MSa/s ADC and an input front-end of about 100 MHz.