New oscilloscope from Fnirsi DPOS350P

[Ivont]

this error which you will see in the picture if you look carefully

Well I don't know what the error is and I've looked closely. Is it because the generator is set to squarewave but the display of same is a sine? I only think this because the discussion is about the generator not remembering its setting, but that in itself wouldn't be too bad (lots of things seem to do that), so I can only think that it is much worse and showing you that it is doing one thing but actually doing another?

Do I get the prize? There was a prize, wasn't there? Otherwise why make it a secret that only the super-attentive will notice? You could have given a clue, or even a white-on-white spoiler if it hurt too much to just say what the problem was or what the screen is showing.

Soooooo.  Very interesting but never mind.🤔🤔🤔

[Ivont]

I have always known that the Chinese are a great nation.      There is no more powerful nation.      The only ones who produce everything.  I am glad that there are such people, such a people.

[BrianRosenthal]

If yangyao is still watching this thread, a couple of items for your next firmware update:

1.  It doesn't appear that the trigger mode is being saved in the configuration.  Set it to Normal, save, power off and reload and the trigger remains at Auto.

2.  There doesn't appear to be a way to check the installed firmware version.

Thanks!

[Ivont]

I didn't understand anything.  Very strange.  What is it about?  It's already in English, now what are you telling me to do?

[Ivont]

If yangyao is still watching this thread, a couple of items for your next firmware update:

1.  It doesn't appear that the trigger mode is being saved in the configuration.  Set it to Normal, save, power off and reload and the trigger remains at Auto.

2.  There doesn't appear to be a way to check the installed firmware version.

Thanks!

Now I understand you.  That's right.

[Ivont]

A slider can be added to accurately measure the location.  When the cursor is moved, a precision position slider should also appear.  After 1 second to hide.

[Ivont]

Hello friends.  Can someone send me a detailed description of sampling methods in oscilloscopes.  Sampling, how it syncs. My guess is that when a selected trigger is matched, sampling starts. With this oscilloscope, how much is the buffer memory that must temporarily store the data from the discrete signal.

[Etrius]

Hello everyone. I would like to know if the DPOS350P I just purchased is defective. When viewing a simple 50 Hz square wave produced by the internal generator, the displayed wave is not square at all but shows rather sharp peaks on the switching edges. I tried changing the probe, the attenuation (1X or 10X), and the channel (CH1 or CH2), but the problem persists. Measuring the same wave with another oscilloscope, however, it is square. Can anyone give me feedback on performing this measurement?

[Sorama]

Tune the probe.

[BillyO]

Hello everyone. I would like to know if the DPOS350P I just purchased is defective. When viewing a simple 50 Hz square wave produced by the internal generator, the displayed wave is not square at all but shows rather sharp peaks on the switching edges. I tried changing the probe, the attenuation (1X or 10X), and the channel (CH1 or CH2), but the problem persists. Measuring the same wave with another oscilloscope, however, it is square. Can anyone give me feedback on performing this measurement?

Mine looks square, so you might have an issue with your scope.  Can we see how you are doing the probing?

[BillyO]

Tune the probe.

Probe compensation is not applicable when the probe is in 1x.  Also, the relaxation tine is way longer than could be adjusted for via compensation with the probe in 10x.

[Grandchuck]

@Etrius
Do you have a BNC jumper cable you can try?

[Ivont]

Try another probe.  The problem is in the output or input circuit.

[Atlan]

Try measuring DC voltage in DC mode of the oscilloscope. I guess the ACDC coupling switching is not working.

[Ivont]

I have a problem with 50MHz.   When the generator is at high frequency, and the amplitude is 1V, it shows 1.37V.  There is also a slight flickering of the sine wave.

[BillyO]

I have a problem with 50MHz.   When the generator is at high frequency, and the amplitude is 1V, it shows 1.37V.  There is also a slight flickering of the sine wave.

How are you connecting the generator to the scope?

I get 900mV, but also a very slight instability.

[Ivont]

I connect it, the input probe and the cable from the generator.

[BillyO]

Odd then.  Using a direct connection I get 900mV.

[Etrius]

Thanks for the feedback, so it's just my faulty device.
To perform the measurement, I simply connected the generator output to the oscilloscope input using the supplied cables. When measuring with another oscilloscope, the displayed waveform is square.

[Etrius]

Try measuring DC voltage in DC mode of the oscilloscope. I guess the ACDC coupling switching is not working.

I thought it was a design issue, not a problem with my device. I note that both channels are displaying the exact same anomaly. If it were a problem with the input stage, it would be highly unlikely that the same problem would recur on both channels. The AC/DC switching also seems to work properly, and when measuring a DC voltage, the reported value is correct (the error is less than 5%). Personally, I can't explain it...
Of course, I also tried updating the firmware.

[Etrius]

@Etrius
Do you have a BNC jumper cable you can try?

Unfortunately, no. But we're talking about a frequency of 50Hz, not 50MHz.

[Ivont]

@Etrius
Do you have a BNC jumper cable you can try?

Unfortunately, no. But we're talking about a frequency of 50Hz, not 50MHz.

Can you play on 10MHz.  How it looks.  To me, it's far from a rectangular signal.

[Ivont]

I tried the generator on two more oscilloscopes.    The amplitude at high frequencies becomes unstable and so does the phase.    I tried it on DPOX180H and Zoyi zt703s.    The latter shows exactly the frequency and voltage.  At sine wave, 50MHz.

[Ivont]

I connected the generator to the oscilloscope.  I used a cable with two BNCs.  At 50Hz, it shows the same signal as the Etrius.

[Ivont]

This thing got on my nerves.  When I have connected the generator at 50MHz, with a probe from the oscilloscope, to its generator, x10, it shows 1.12V.  When I switch to x1 it shows 0.328V.  The generator is at 1V.