New toy(?) scope Fnirsi DPOX180H, claimed 180MHz/500MSps (May 2023)

[slavoy]

I just don't understand this youtube reviews. In any video, they don't measure basic crucial parameters like bandwidth or sampling. The guy is surprised that he has an amplitude of 1.11Vpp instead of 1Vpp at 100MHz, and he connected the generator directly without a terminator... it's useless. Simply connect that terminator, and for sure, there will be a significant drop in amplitude at 100MHz.
I perform the sampling check in a hardware-based manner by connecting to the A/D converter on the board and measure its frequency and all doubts are gone.
Sooner or later, I will have this oscilloscope in my workshop and there will be a review, but for now, I wanted to assess whether it's worth buying just for tests or if it's better to request a sample.

[Aldo22]

I just don't understand this youtube reviews. In any video, they don't measure basic crucial parameters like bandwidth or sampling.

Yes. With some Youtube testers, I get the impression that they have even less of a clue than I do, and that means something!
Others get the devices for free from the manufacturers and in return are more interested in presenting the features and bling-bling than in testing the limits.
Maybe we should create a guide on how Youtubers should test such devices. 

[RAPo]

And then we should make that list mandatory for any "send for free" review, enforced by youtube ;-)

[mebel]

Some resistors and capacitors showed on the photo  are soldered by hand. It's rather bad soldering with flux residue.  I saw a different photo probably on this topic (i cannot find it now) with the same soldering.

[mebel]

Other side of the PCB.

[Escalator]

Are there any western EU resellers yet, but it will likely be way more expensive, but it looks like it come down in price quite a bit lately, and atm around 110 Euro with delivery & VAT included.
https://www.eevblog.com/forum/testgear/new-toy()-scope-fnirsi-dpox180h-claimed-180mhz500msps-(may-2023)/msg4882829/#msg4882829

Even cheaper for certain regions like Poland Czech,Hungary, Slovakia, Slovenia, Greece as they all got extra dedicated product-coupon. (BGCZBP10, BG6MEGA32, BGRJ180H)
but overall it looks like its a mixed halfbaked cake, this handheld Fnirsi scope.

[svetlov]

it is not clear how the FNIRSI DPOX180H interprets a square wave
these are screenshots from the review - at this frequency of 7.2 MHz, Rigol's signal is similar to what it can display within its capabilities - the output of the SI5351 is a square wave with a fast rise time - something like this it looks like on Siglent at a frequency of 10 megahertz

[RAPo]

Really 7.2MHz? the screen dump on the DPOX says 22.89MHz

it is not clear how the FNIRSI DPOX180H interprets a square wave
these are screenshots from the review - at this frequency of 7.2 MHz,

[svetlov]

Arduino module on SI5351 on the display shows 7.2 MHz

[Aldo22]

Really 7.2MHz? the screen dump on the DPOX says 22.89MHz

That's the second (blue) channel...

it is not clear how the FNIRSI DPOX180H interprets a square wave
these are screenshots from the review - at this frequency of 7.2 MHz, Rigol's signal is similar to what it can display within its capabilities - the output of the SI5351 is a square wave with a fast rise time - something like this it looks like on Siglent at a frequency of 10 megahertz

I don't trust this YT tester and his setup.
I also wonder if a 50MHz Rigol is really a good reference to test a (supposedly or really) 180MHz device?
Also, no one seems to make a distinction between one and two active channels although it is documented that with two channels it has only 90MHz bandwidth etc.
Nobody seems to have the desire to really test this oscilloscope. 

[svetlov]

  Aldo22 -Rigol DS 1052E has an honest 1 gigasamples per second and besides it is converted to 100 megahertz - Dave tested it to minus 3 dB and he got an  136 megahertz
it is in this video of his from 15 minutes 20 seconds
used here , the Williams generator is just what  need to test Oscilloscopes

 in theory, if the FNIRSI DPOX180H has the second channel enabled, the sampling rate will drop by half - yes - but no one has yet checked the sampling rate in single-channel mode

[Aldo22]

  Aldo22 -Rigol DS 1052E has an honest 1 gigasamples per second and besides it is converted to 100 megahertz - Dave tested it to minus 3 dB and he got an honest 130 megahertz

Yes, but the one from YT Richard is not. He says it is an unmodified 50MHz Rigol (at 24:25).
Anyway, I just don't get the impression that this scope test is very well thought out.
As I said, I don't even know if channel 2 is on or off.

[radiolistener]

it is not clear how the FNIRSI DPOX180H interprets a square wave
these are screenshots from the review - at this frequency of 7.2 MHz

how si5351 is connected to oscilloscope? Direct coax with 50Ω terminator?

Probably they using some incorrect algorithm in order to show "beautiful wave" instead of real signal...
As we saw before they don't show waveform details such as noise and overshoot... It seems that they shot themselves in the foot by using such "filtering", so it cannot show square wave with a fast rise time properly...

I wonder to know how they acquire buffer with 5 GS/s resolution at 5 ns/div on 100-200 MHz ADC? Probably here is the answer why it shows incorrect waveform...

Nice attempt to manufacture device, the UI looks really nice with this cool digital phosphor, but it seems that you cannot believe it 
This is classic issue of such Chinese devices...

[svetlov]

screenshot with 50 ohm Siglent input not mine, taken from another forum http://www.cqham.ru/forum/showthread.php?38850-%CA%E0%F7%E5%F1%F2%E2%EE-%F1%E8%E3%ED%E0%EB%E0-SI5351/page3
and this screenshot from the video where the comparison with the rigol is connected directly to the output of the SI5351 - the photo shows

[radiolistener]

Don't use probe, use direct coax cable with 50Ω terminator on oscilloscope side. Probe has very crooked frequency response, you cannot see good square wave even with good probes.

[Aldo22]

I wonder to know how they acquire buffer with 5 GS/s resolution at 5 ns/div on 100-200 MHz ADC? Probably here is the answer why it shows incorrect waveform...

Nice attempt to manufacture device, the UI looks really nice with this cool digital phosphor, but it seems that you cannot believe it 
This is classic issue of such Chinese devices...

I would like to see a decent test first before judging the device.
At least, this time they explain unusually precisely in their promotional material how the thing works.

[NoMoreMagicSmoke]

Really 7.2MHz? the screen dump on the DPOX says 22.89MHz

That's the second (blue) channel...

it is not clear how the FNIRSI DPOX180H interprets a square wave
these are screenshots from the review - at this frequency of 7.2 MHz, Rigol's signal is similar to what it can display within its capabilities - the output of the SI5351 is a square wave with a fast rise time - something like this it looks like on Siglent at a frequency of 10 megahertz

I don't trust this YT tester and his setup.
I also wonder if a 50MHz Rigol is really a good reference to test a (supposedly or really) 180MHz device?
Also, no one seems to make a distinction between one and two active channels although it is documented that with two channels it has only 90MHz bandwidth etc.
Nobody seems to have the desire to really test this oscilloscope. 

I agree with you that the YT scope test is not well thought out. I'm not quite sure it would matter though. Here is a 10 megahertz signal from a SI5351 both with and without proper termination on an 100 megahertz scope. The blue trace is connected directly to the scope without a terminator and the yellow is with the proper 50 ohm termination. Both traces still look reasonably close to a square wave whereas the screenshots of the DPOX180H look nothing like the expected square wave. Even if both channels were on limiting the bandwidth to 90 MHz the signal should still be recognizable as a square wave.

[Aldo22]

I agree with you that the YT scope test is not well thought out. I'm not quite sure it would matter though. Here is a 10 megahertz signal from a SI5351 both with and without proper termination on an 100 megahertz scope. The blue trace is connected directly to the scope without a terminator and the yellow is with the proper 50 ohm termination. Both traces still look reasonably close to a square wave whereas the screenshots of the DPOX180H look nothing like the expected square wave. Even if both channels were on limiting the bandwidth to 90 MHz the signal should still be recognizable as a square wave.

That could be. I don't know, but I would like to know.
Anyway, the screen at ~20MHz looks pretty much like the one from the Rigol.
I can't really imagine the device is giving up at a 10MHz square wave from a SI5351.

[RAPo]

Oke, I'll bite. In this file, you see how the DPOX reacts to a square wave file from a MAX2871 at max amplitude.
There are two series images.
Serie 1: only channel 1 is active.
Serie 2:both channels are active, triggering on channel 2.
The measurement is taken with 1x probe attenuation, terminated with a 50Ohm at the input of the scope.

[dietert1]

One can call this a toy.
The front end of that scope is resonant at about 200 MHz, with roughly 25 % maybe 30 % overshoot. Professional digital scopes are tuned to 5 % or less overshoot. Non-resonant means their front ends are capable to at least twice the bandwidth, without any steep filter.

Regards, Dieter

[Aldo22]

Oke, I'll bite. In this file, you see how the DPOX reacts to a square wave file from a MAX2871 at max amplitude.
There are two series images.
Serie 1: only channel 1 is active.
Serie 2:both channels are active, triggering on channel 2.
The measurement is taken with 1x probe attenuation, terminated with a 50Ohm at the input of the scope.

The square wave looks good in 1CH mode up to 60MHz.
For the 2CH mode, 40MHz is a bit much as a start.
I think it delivers for its price ($126 at Banggood) as far as I can see.

[radiolistener]

At least, this time they explain unusually precisely in their promotional material how the thing works.

4 x 125 MS/s in interleave is 500 MS/s, but their WAV file taken at 5 ns/div contains waveform with 5 GS/s sample rate (300 samples per screen which contains 12 divs x 5 ns = 0.2 ns per sample). And this is not interpolation, because it has one sample spikes...

So there is no answer how they acquire it with 5 GS/s resolution.

[rhb]

One can call this a toy.
The front end of that scope is resonant at about 200 MHz, with roughly 25 % maybe 30 % overshoot. Professional digital scopes are tuned to 5 % or less overshoot. Non-resonant means their front ends are capable to at least twice the bandwidth, without any steep filter.


Regards, Dieter

You've obviously not used a LeCroy DDA-125 1.5 GHz DSO.  Some use cases prioritize risetime over over shoot.  I adjust analog scopes to <3%.

DSO designers violate almost every rule in data acquisition.

Reg

[dietert1]

It depends on what you want to do. Certainly for repairs having this handheld scope is better than having no scope. Some people think in terms of audio work, video work, digital etc. For example you can use the scope to look at a RS232 or I2C interface. USB and SPI will be more difficult. What is the record length? Will there be a decoder?
If one wants to do a measurement, the deviations can be 25 or 30 % as i wrote. So you will see whether there is a signal but it will be difficult to characterize. For example it will be difficult to say whether a transmission line is terminated properly.
Instead of buying toy electronics i always tried to get a pre-owned professional scope. The first one was a Tectronix 2465. For digital scopes it was Lecroy plus some VXI stuff from HP. I am wondering about the safety of handheld scopes for measurements on power supplies connected to mains. Probably one should use an isolation transformer like with other scopes. If you are serious about electronics, you will need more than US$ 125.

Regards, Dieter

[RAPo]

Fnirsi has acknowledged that this is a bug:

Hi, dear friend
We confirm on our device;
This phenomenon occurs on the device; it may be abnormal display;
The technician recommends that you restore the device to factory settings;
Just check the device status after reset;
Sincerely,

Warning this deletes your current saved configuration.
Of course, if you delete all measurements from channel 2, the wrong number appears again.

I discovered a tiny bug. If you go to the param measure menu and then channel 2, remove all measure items, and go out of the menu. The screen shows 1 items instead of 0.