The first two are of my SDS7102 and Tek DPO20204 attached to the same signal generator using their supplied probes.
The Tek is being triggered off of the Owon's trigger out since the noise seems to be synchronized with the Owon's sweeps and this allows it to be better captured visually.
The next is of the Tek connected to the same signal generator, but with the Owon turned off and it triggered internally. The last is of the Owon connected to the signal generator using a coaxial cable and a 50 Ohm straight through terminator.
with probes directly to signal gen output, right?
ok, and how it looks when Tek is using own trigger and Owon is on? Is Tek having then clean picture and Owon noisy one?
so here im principe both connected directly to signal gen and triggering with own internal trigger, they looks ok, but for sure coax cable is part of the answer here.
I have bought two brand new BNC terminators 50R and tried them. There is absolutely no difference between "fully inserted plug" or "just touching". I attach a picture which should count for all the four that you have asked me.
The Owon people have come back to me and told me not to expect too much from the scope as it is a cheap scope. However I genuinely think mine is broken as there is all this noise which renders the scope almost useless for signals below 100mV RMS or thereabouts.
But it is clear that if signal what oscilloscope see in its BNC input do not have noise also oscilloscope do not internally add this noise to signal.
My old, 30+ year old, 20MHz scope displays the same curves with no problems.
Here are some more pictures to demonstrate the problem. Scope was away from any sources of interference and not connected to the mains.
The signal is 120mV pk-pk at 1KHz. This is not a "small" signal. I repeat : it is 120mV pk-pk.
The situation gets worse, much worse, as the signal gets weaker. I even wonder why bother have a "5mV" or a "10mV" scale when in reality they are so useless. Also the only way to get a clear picture is to "limit" the scope to 20MHz, in which case why advertise it as a "100MHz".
Picture 1 shows the amount of random noise :
Picture 2 shows the same but with the scope set to 20MHz.
Picture 3 shows the same but with the addition of "sample" rather than "peak". Had I put the screen persistence on (like old phosphor displays) it would also be much worse.
Here are some more pictures to demonstrate the problem. Scope was away from any sources of interference and not connected to the mains.
The signal is 120mV pk-pk at 1KHz. This is not a "small" signal. I repeat : it is 120mV pk-pk.
The situation gets worse, much worse, as the signal gets weaker. I even wonder why bother have a "5mV" or a "10mV" scale when in reality they are so useless. Also the only way to get a clear picture is to "limit" the scope to 20MHz, in which case why advertise it as a "100MHz".
Picture 1 shows the amount of random noise :
Picture 2 shows the same but with the scope set to 20MHz.
Picture 3 shows the same but with the addition of "sample" rather than "peak". Had I put the screen persistence on (like old phosphor displays) it would also be much worse.
There is something wrong.
Here some images.
Now here used Owon probe what is connected to 50ohm terminated signal generators output. (50ohm source need 50ohm termination for correct level.)
All shots are real time single captures and of course without averaging. Normal acquire.
for 300kHz used HP8644B signal generator (it have very clean signal)
for 1kHz used HP3314A "noise gener....oops... function generator"
Owon used for test:
SDS7102V series: 1246xxx
Version 2.8.2
Probe: "T5100" (Oscilloscope normal accessory)
Here are some more pictures to demonstrate the problem. Scope was away from any sources of interference and not connected to the mains.
The signal is 120mV pk-pk at 1KHz. This is not a "small" signal. I repeat : it is 120mV pk-pk.
The situation gets worse, much worse, as the signal gets weaker. I even wonder why bother have a "5mV" or a "10mV" scale when in reality they are so useless. Also the only way to get a clear picture is to "limit" the scope to 20MHz, in which case why advertise it as a "100MHz".
Picture 1 shows the amount of random noise :
Picture 2 shows the same but with the scope set to 20MHz.
Picture 3 shows the same but with the addition of "sample" rather than "peak". Had I put the screen persistence on (like old phosphor displays) it would also be much worse.
Here are some more pictures to demonstrate the problem. Scope was away from any sources of interference and not connected to the mains.
The signal is 120mV pk-pk at 1KHz. This is not a "small" signal. I repeat : it is 120mV pk-pk.
The situation gets worse, much worse, as the signal gets weaker. I even wonder why bother have a "5mV" or a "10mV" scale when in reality they are so useless. Also the only way to get a clear picture is to "limit" the scope to 20MHz, in which case why advertise it as a "100MHz".
Picture 1 shows the amount of random noise :
Picture 2 shows the same but with the scope set to 20MHz.
Picture 3 shows the same but with the addition of "sample" rather than "peak". Had I put the screen persistence on (like old phosphor displays) it would also be much worse.
Did you use the supplied probes to connect to the signal source in picture 1? If so, was the probe set to 10x or 1x? I am trying to reproduce on my own SDS7102 as I believe that mine has a similar defect. Do you have a coaxial cable you can use? On mine, the noise seems to be external (but generated by the Owon itself) to the actual signal path as it is greatly attenuated when using a fully shielded connection between the scope and the signal generator.
Here are some more pictures to demonstrate the problem. Scope was away from any sources of interference and not connected to the mains.
The signal is 120mV pk-pk at 1KHz. This is not a "small" signal. I repeat : it is 120mV pk-pk.
The situation gets worse, much worse, as the signal gets weaker. I even wonder why bother have a "5mV" or a "10mV" scale when in reality they are so useless. Also the only way to get a clear picture is to "limit" the scope to 20MHz, in which case why advertise it as a "100MHz".
Picture 1 shows the amount of random noise :
Picture 2 shows the same but with the scope set to 20MHz.
Picture 3 shows the same but with the addition of "sample" rather than "peak". Had I put the screen persistence on (like old phosphor displays) it would also be much worse.
Did you use the supplied probes to connect to the signal source in picture 1? If so, was the probe set to 10x or 1x? I am trying to reproduce on my own SDS7102 as I believe that mine has a similar defect. Do you have a coaxial cable you can use? On mine, the noise seems to be external (but generated by the Owon itself) to the actual signal path as it is greatly attenuated when using a fully shielded connection between the scope and the signal generator.
Yes, I used the supplied probes for this test. Set to 1X. Source resistance about 600R. Signal 120mV pk-pk.
I forgot to say, the ONLY way to get a steady curve, is with trigger set to "HF". If you are looking at DC forget it.
As far as I can see, all scopes from 2012 have Ethernet.
Other:
This suspected noise problem in some units need study more.
It looks like if it come from oscilloscope it do not pollute internally signal pathway. But if there is strong noise generated by oscilloscope itself it may connect externally to signal.
Later I will take one oscilloscope open and do some tests.
My testing definitely seems to indicate that it is generated by the oscilloscope, but does not pollute the internal signal path. The noise appears to be somewhat broadband in nature ranging from around 70 - 100 MHz, which explains why when you apply the 20 MHz bandwidth limiter it reduces it. It almost looks like some kind of ringing.
My testing definitely seems to indicate that it is generated by the oscilloscope, but does not pollute the internal signal path. The noise appears to be somewhat broadband in nature ranging from around 70 - 100 MHz, which explains why when you apply the 20 MHz bandwidth limiter it reduces it. It almost looks like some kind of ringing.
Yes I know this. Of course fast rising/falling edge include lot of frequency components.
Also there may be internal ringing due to these fast edges.
Your message Reply #880 at 10:20:51 AM
And there image: 20130130_264121.bmp
It tells to me "lot of" things.
Now is time to do lab work for this. I will dismantle one SDS and look more deep things related to this.
Information of a potential problem now is enough here. Now need starting study. What is needed now is only to work in peace and arrange time slot for do it. I will also contact with Owon after I have more than suspects and nearly empty hand. (I have a couple of suspects, it should be examined.)
It is fully possible there is only some units if problem is example in some circuits for filtering these switch mode noise... perhaps lack of some component or "whatever"...
What is your hunch? Is it maybe a manufacturing line problem (eg dirt on the tracks), a failing component, or a flaw in the design ?
My testing definitely seems to indicate that it is generated by the oscilloscope, but does not pollute the internal signal path. The noise appears to be somewhat broadband in nature ranging from around 70 - 100 MHz, which explains why when you apply the 20 MHz bandwidth limiter it reduces it. It almost looks like some kind of ringing.
Yes I know this. Of course fast rising/falling edge include lot of frequency components.
Also there may be internal ringing due to these fast edges.
Your message Reply #880 at 10:20:51 AM
And there image: 20130130_264121.bmp
It tells to me "lot of" things.
Now is time to do lab work for this. I will dismantle one SDS and look more deep things related to this.
Information of a potential problem now is enough here. Now need starting study. What is needed now is only to work in peace and arrange time slot for do it. I will also contact with Owon after I have more than suspects and nearly empty hand. (I have a couple of suspects, it should be examined.)
It is fully possible there is only some units if problem is example in some circuits for filtering these switch mode noise... perhaps lack of some component or "whatever"...
What is your hunch? Is it maybe a manufacturing line problem (eg dirt on the tracks), a failing component, or a flaw in the design ?
My testing definitely seems to indicate that it is generated by the oscilloscope, but does not pollute the internal signal path. The noise appears to be somewhat broadband in nature ranging from around 70 - 100 MHz, which explains why when you apply the 20 MHz bandwidth limiter it reduces it. It almost looks like some kind of ringing.
Yes I know this. Of course fast rising/falling edge include lot of frequency components.
Also there may be internal ringing due to these fast edges.
Your message Reply #880 at 10:20:51 AM
And there image: 20130130_264121.bmp
It tells to me "lot of" things.
Now is time to do lab work for this. I will dismantle one SDS and look more deep things related to this.
Information of a potential problem now is enough here. Now need starting study. What is needed now is only to work in peace and arrange time slot for do it. I will also contact with Owon after I have more than suspects and nearly empty hand. (I have a couple of suspects, it should be examined.)
It is fully possible there is only some units if problem is example in some circuits for filtering these switch mode noise... perhaps lack of some component or "whatever"...
What is your hunch? Is it maybe a manufacturing line problem (eg dirt on the tracks), a failing component, or a flaw in the design ?
akis, rf-loop -- my supplier pulled another scope from stock and was able to reproduce the noise problem, so it appears that this affecting more than just a few units. Hopefully we can get a fix from Owon (perhaps through rf-loop's investigations), since the only alternative seems to be to return the unit for a refund. That would be a real shame as it is hard to find a portable unit with similar specifications that is even close to the price of the SDS7102.
My testing definitely seems to indicate that it is generated by the oscilloscope, but does not pollute the internal signal path. The noise appears to be somewhat broadband in nature ranging from around 70 - 100 MHz, which explains why when you apply the 20 MHz bandwidth limiter it reduces it. It almost looks like some kind of ringing.
Yes I know this. Of course fast rising/falling edge include lot of frequency components.
Also there may be internal ringing due to these fast edges.
Your message Reply #880 at 10:20:51 AM
And there image: 20130130_264121.bmp
It tells to me "lot of" things.
Now is time to do lab work for this. I will dismantle one SDS and look more deep things related to this.
Information of a potential problem now is enough here. Now need starting study. What is needed now is only to work in peace and arrange time slot for do it. I will also contact with Owon after I have more than suspects and nearly empty hand. (I have a couple of suspects, it should be examined.)
It is fully possible there is only some units if problem is example in some circuits for filtering these switch mode noise... perhaps lack of some component or "whatever"...
What is your hunch? Is it maybe a manufacturing line problem (eg dirt on the tracks), a failing component, or a flaw in the design ?
akis, rf-loop -- my supplier pulled another scope from stock and was able to reproduce the noise problem, so it appears that this affecting more than just a few units. Hopefully we can get a fix from Owon (perhaps through rf-loop's investigations), since the only alternative seems to be to return the unit for a refund. That would be a real shame as it is hard to find a portable unit with similar specifications that is even close to the price of the SDS7102.
Ha HA Ha HA , that was funny! .
And even more so in brackets after
Owon have holiday 7th to 17th Feb due to Spring Festiwal time.
(whole China is more or less on the holiday) and after holiday, no one know who workers return back (hehe) from holiday and so or so but after holiday all services are heavy loaded, rush and queyed....
Disclaimer: This next all is now my unofficial opinion!
After some talking with Owon about some findings (in scope internals) I believe there is coming some, perhaps very simple, solution but not just immediately. There is not just one problem... it is perhaps group of problems perhaps related to some components parameters and perhaps also PCB design (This power supply and adapter card is very new version if looks also used components) With very fast rising edges there need handle tens and hudreds of megaherz freq components in single simple 50kHz switch mode regulator. Now something have changed and...