EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: jetigm on December 10, 2020, 11:05:08 am
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Hi folks,
I recently bought the SDS2200X-E and get this strange measurement effect and I try to figure out is everything ok with the scope or it is defective and I should ask for a replacement. Please give some opinion on this.
So the problem appears at least at this measurement conditions:
1. Probe and scope setted to 1X.
3. Scope is switched to the <=100mV/div @ SDS2200X-E and in case of Rigol - <=200mV/div.
2. Input signal is 1KHz and 3V amplitude.
The scope displays what is shown at the picture but not the flat bottom line of the signal as I suppose it should be.
This effect doesn't happened at 10X probe or 1V input signal amplitude.
When I switch to the 100mV/div @ SDS2200X-E and 200mV/div @ Rigol the relay inside is clicking what makes me think that different circuits is become active and this is more likely the hardware bug.
I have upgraded the SDS2200X-E firmware but it doesn't helped.
Both scopes has very similar behavior and I am confused - where the problem is and are these scopes is defective?
Or maybe all scopes in this price range behave the same and only more expensive ones don't have this effect?
Or everything is ok with the scopes and this effect caused by some other reasons?
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Hi folks,
I recently bought the SDS2200X-E and get this strange measurement effect and I try to figure out is everything ok with the scope or it is defective and I should ask for a replacement. Please give some opinion on this.
So the problem appears at least at this measurement conditions:
1. Probe and scope setted to 1X.
3. Scope is switched to the <=100mV/div @ SDS2200X-E and in case of Rigol - <=200mV/div.
2. Input signal is 1KHz and 3V amplitude.
The scope displays what is shown at the picture but not the flat bottom line of the signal as I suppose it should be.
This effect doesn't happened at 10X probe or 1V input signal amplitude.
When I switch to the 100mV/div @ SDS2200X-E and 200mV/div @ Rigol the relay inside is clicking what makes me think that different circuits is become active and this is more likely the hardware bug.
I have upgraded the SDS2200X-E firmware but it doesn't helped.
Both scopes has very similar behavior and I am confused - where the problem is and are these scopes is defective?
Or maybe all scopes in this price range behave the same and only more expensive ones don't have this effect?
Or everything is ok with the scopes and this effect caused by some other reasons?
No that is not defect, you're simply overdriving scopes input amplifiers. Once top or bottom of signal goes off the screen, you can expect distortion. Same as you would when overdriving audio amplifier..
Older analog scopes had different input sections (attenuators and amplifier itself) and worked with much higher internal voltages so had larger dynamic range before saturating. So they were more resilient to this behaviour, although some models more, some less.
And more expensive scopes will have same architecture and same problem..
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Thanks a lot!
If so, than I will keep my brand new SDS2200X-E :)
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Thanks a lot!
If so, than I will keep my brand new SDS2200X-E :)
You're welcome!
And if you search here on EEVBLOG, you will realize you have 350MHz scope .. ^-^
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Thanks a lot!
If so, than I will keep my brand new SDS2200X-E :)
can you show 100 Hz square wave on your oscilloscope with DC and AC coupling?
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can you show 100 Hz square wave on your oscilloscope with DC and AC coupling?
Currently no, I don't have a generator yet, only can play around with internal 1K gen.
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Here is Siglent SDS1102X. Gen output is 50 Ohm, oscilloscope input 50 Ohm.
100 Hz square wave with a flat top and bottom.