Another DSO+DMM - Zeeweii DSO3D12, claimed 120MHz/250MSps (june 2023)

[Fungus]

It's just a screenshot.

[taligentx]

Hi folks,

Thanks to the great info here and in the DSO2512G thread, I picked up a DSO3D12 from the Zeeweii official Aliexpress storefront during the 11.11 sale. It arrived with firmware 3.0.6-III:



The support site still shows 3.0.5-III. Any ideas on the updates in this firmware or functionalities to test? I've requested info about this firmware from Zeeweii in case there are notes available.

-Nikhil

[BillyO]

Hmm, I wish I knew about it.  I have requested a copy from Zeeweii.

[beenai2018]

Anyone here have non Zeeweii branded unit ? Im seeing "Zeeweii company store" ,"zeeweii official store" ,"kkmoon store" etc. selling the same item on Aliexpress..

Curious to know if they are all selling the same unit or  changing firmware etc. There is minor chatter about that in the thread but nothing to sway me either way ..

[motoge]

Thanks for the article post．
Mine is version V3.05．
The current problem is
The bandwidth in the automatic measurement mode is the period of the band．
and


Taking a screenshot while displaying cursor measurements results in overlapping displays．

How about version V3.06?

[spikey1973]

@Fungus: thanks, good to know..
@taligentx: thanks for telling us, I didn't check mine and I ordered it at the same shop, same time and indeed mine is 3.0.6-III to.
I connected it to my laptop, but I did not see a drive available, would love to see if I could download the screenshot images, but if no dribe is visible...

Am very interested in the reply from Zeeweeii when you get it.

@motoge: I hope this version solves your issues too!

Kind greats

Matthieu

[taligentx]

Taking a screenshot while displaying cursor measurements results in overlapping displays.

Hi @motoge - if you mean the screenshot sequence number, yes, it still displays in the upper left corner of the screenshot and obscures that part of the image:

The bandwidth in the automatic measurement mode is the period of the band.

Do you have a test sequence for this issue that can use the built-in signal generator?

[_RUS73_]

I measured at 500μS but the data is not displayed.

To correctly display all signal parameters, at least a couple of full signal periods must be displayed on the screen.

[motoge]

That's right. The display overlaps.
The internal transmitter is the only option I have.

[motoge]

The same waveform was displayed on other oscilloscopes.

Measurement was possible with just one waveform
In the case of DSO120M

[BillyO]

Anyone here have non Zeeweii branded unit ? Im seeing "Zeeweii company store" ,"zeeweii official store"

These two are the Zeeweii stores.  I've no idea why they have two, but they did confirm to me that both of these are actaully Zeeweii.  They also confirmed that many other stores sell their products.

[spikey1973]

it's fairly easy to confirm if "2 or more" stores are actually the same on AE.
under the store name there is a "link" to store-information -> company license:
here you can find the tax-number. if they are the same they are the same store.

IMHO they make more than one store for one or more of the following reasons:
* one is a choice store, the other isn't
* posibility to make different offerings for the same item
* being "visually" more present compared to the competition, specifically interesting when searhing for one specific item.

so when searching for a zoyt 703, you get 2-3-4 or more ads, all the one stores.
The smaller stores will have just one add, mostly not a choice, maybe even lower price but with shiping costs, having no store name, but a number (guess the names are expensive),

this all ofcourse to draw us customers in.

kind greats

Matthieu

[BillyO]

Some companies like Zeeweii or FNIRSI do not use choice, but their free shipping is very fast.  Never had an issue with either.

[_RUS73_]

Has anyone tested the generator with a reference meander signal?

Watching amateurs' tests on YouTube, it is clear that the generators do not produce a reference signal at all. These are screenshots of the results from several videos.

I have a smd txco generator for 26 megahertz. I assembled it with a 3.3v supply and decoupled the output with a 10pf capacitor. But its signal does not even remotely resemble a square wave.

[BillyO]

I don't quite understand what you want to know.

The JDS6600 60MHz - the 60MHz is for sine wave only and the square wave is only specified to be useful to 10MHz.  However, that screen shot you show does NOT look like any JDS6600 I know of.  Maybe they really are amateurs of the worst kind.

Here is my DSO3D12 with my JDS6600 (60MHz) @ 10MHz, 20MHz and 24MHz.  (sorry, had probe set to 10X and the focus is lousy)

And I get pretty much exactly the same with my Siglent SDS2504 scope, so it's no the ZEEWEII, is the the JDS6600.

[_RUS73_]

Hmm... That's weird. Your signal is very suppressed. Are you sure the probe is in the 10x position because it doesn't look like it at all. Can you repeat the measurements?

.

[BillyO]

Obviously the scope is set to 10x.  This only changes the vertical scaling.

I did not use a probe.  The measurements were made using a 50Ω coax from the FG to the scope through a 50Ω passthrough terminator at the scope end.  This is the correct way to do it.  I'm not sure how the "amateurs" you looked at on YT did it, but I'm almost 100% sure they did it incorrectly just from viewing your screen shots. 

The signal is not suppressed.   That is what the JDS6600 produces.  Again, as I said, the waveform is essentially the same viewed on my 500MHz Siglent scope.

In what way, exactly, would you like me to repeat the measurements?

[_RUS73_]

(50Ω passthrough terminator) do you mean 50 ohm balanced load(RF) for the generator?

[BillyO]

(50Ω passthrough terminator) do you mean 50 ohm balanced load(RF) for the generator?

The JDS6600 has an output impedance of 50Ω.  When you connect it via a 50Ω coax cable to an oscilloscope that has a high impedance input you need to terminate the cable at the scope end with a 50Ω load.  This is is normally done with a 50Ω passthrough or feed-through terminator.  Google it.

See the one I used below.  And have a look at this video: https://youtu.be/W_Jy_sdpv9Y

[_RUS73_]

I think your measurement technique is correct. But there is a nuance with the signal generator. It cannot generate the correct signal shape if there is not only an active load of 50 Ohm, but also a reactive load in the form of cable capacitance and oscilloscope input capacitance. This can be easily verified by using an oscilloscope probe in the 10x position in this chain. Try adding another oscilloscope probe when measuring.

[wasedadoc]

@_RUS73_

You seem confused:

1.  "an active load of 50 Ohm". Why have you written "active"?

2.  "50 ohm balanced load(RF)". Why have you written "balanced"?  Neither the generator output nor the scope input is balanced.

[BillyO]

I think your measurement technique is correct. But there is a nuance with the signal generator. It cannot generate the correct signal shape if there is not only an active load of 50 Ohm, but also a reactive load in the form of cable capacitance and oscilloscope input capacitance. This can be easily verified by using an oscilloscope probe in the 10x position in this chain. Try adding another oscilloscope probe when measuring.

The coax cable is a transmission line with a characteristic impedance of 50Ω.  For it to do it's job properly, it must be fed a signal from a 50Ω source and it must deliver it into a 50Ω termination or the signal will get distorted by reflections.  google "transmission line theory" and read at least the Wikipedia article on the subject: https://en.wikipedia.org/wiki/Transmission_line

Right now I have an injured knee so moving around up and down to the basement lab is difficult for me.  If I can, I will do as you ask but do not expect it soon.  The signal I showed you is correct.

[_RUS73_]

@_RUS73_

You seem confused:

1.  "an active load of 50 Ohm". Why have you written "active"?

2.  "50 ohm balanced load(RF)". Why have you written "balanced"?  Neither the generator output nor the scope input is balanced.

These are the difficulties of communication and understanding the essence through Google Translate:)

Now let's get to the point, and what I wanted to convey.

I got hold of a similar signal generator. The test results showed that connecting the generator via a 50 Ohm cable to the oscilloscope via a 50 Ohm pass-through load terminal to the bnc connector of the oscilloscope distorts the signal (apparently the additional capacitance of the oscilloscope input overloads the generator output). Before connecting the oscilloscope, the signal has a more correct shape. This can be easily verified by connecting a probe with a 10x divider to the circuit. The signal has a more regular shape.

Several rules for conducting their measurements are violated here:
1. The oscilloscope must introduce minimal distortion into the measured circuit.
2. The generator must have sufficient load capacity and produce the correct signal to conduct such measurements.

In this particular case, we can only correct the first point, using the probe in the 10x position to minimize the effect on the signal.

I consider the testing conducted by user BillyO to be unsuccessful due to the impossibility of observing point 2.

[BillyO]

2. The generator must have sufficient load capacity and produce the correct signal to conduct such measurements.

..

I consider the testing conducted by user BillyO to be unsuccessful due to the impossibility of observing point 2.

?  How would you observe this?

The JDS6600 has a 50Ω output.  It's right in the specifications.

You can consider whatever you like.  I tested it properly.  Again, read up about signal transmission lines and get your facts straight - please.  The SG sees 50Ω when it drives a correctly terminated 50Ω coax cable and the JDS6600 was designed specifically to do that.  it WILL NOT see the few pF (maybe 40-50pF) of the scope when connected in this fashion.  Where did you dig up this rubbish?

[_RUS73_]

If you think the added capacitance is small enough to distort the signal, repeat the test with the probe first at 1x, then at 10x.