Author Topic: My Rigol DS1054Z has noise and beam thickness dependency of the vertical offset  (Read 4473 times)

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Online 2N3055

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Exact 125MHz indicates it may be the interleave spur of the ADC. The DS1000Z, if I remember correct, use HMCAD1511, which use 8 small ADCs internally interleaved to act as single 1GSPS, dual 500MSPS, or quad 250MSPS ADCs.
Maybe try different vertical scale to see if the noise is scale dependent.
When I set Coupling – GND in the channel menu, the beam becomes thin and does not depend on the position on the screen. So I assumed the problem is in the input amplifier. But may be you're right, not me. I don't have a schematic diagram so I don't know where the input closes to GND. May be at the ADC input.

Thanks again to everyone who is trying to help me figure out the problem. It is very important to set exactly my measurement conditions when you simulating my case on your devices. It is important that:
- Only one channel is involved.
- Acquire menu: Mode – Normal; MemDepth – Auto or 24.0M pts; Anti-aliasing - OFF.
- Channel menu: Scale – 500mV/Div; BW Limit – OFF; Probe – 10X.
- Slider on the probe must necessarily be set to 10X.
Some of you have attached screenshots in which the probe was set to 1X. But noise is lower in such case and test meander and ramp signals looks more symmetrical on my Rigol (see my screenshots). Please see how test meander will look if the probe is switched to 10X.

They cheated. Setting channel to GND does nothing in real world. Software simply does not read ADC anymore but fixes 0 as value.. So you cannot make any conclusions about input amplifier stages from that. Sorry.
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Offline Anthocyanina

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Exact 125MHz indicates it may be the interleave spur of the ADC. The DS1000Z, if I remember correct, use HMCAD1511, which use 8 small ADCs internally interleaved to act as single 1GSPS, dual 500MSPS, or quad 250MSPS ADCs.
Maybe try different vertical scale to see if the noise is scale dependent.
When I set Coupling – GND in the channel menu, the beam becomes thin and does not depend on the position on the screen. So I assumed the problem is in the input amplifier. But may be you're right, not me. I don't have a schematic diagram so I don't know where the input closes to GND. May be at the ADC input.

Thanks again to everyone who is trying to help me figure out the problem. It is very important to set exactly my measurement conditions when you simulating my case on your devices. It is important that:
- Only one channel is involved.
- Acquire menu: Mode – Normal; MemDepth – Auto or 24.0M pts; Anti-aliasing - OFF.
- Channel menu: Scale – 500mV/Div; BW Limit – OFF; Probe – 10X.
- Slider on the probe must necessarily be set to 10X.
Some of you have attached screenshots in which the probe was set to 1X. But noise is lower in such case and test meander and ramp signals looks more symmetrical on my Rigol (see my screenshots). Please see how test meander will look if the probe is switched to 10X.

before, i was using a BNC cable straight from the generator into the scope. Now i'm using a 200MHz probe set to 10x straight into the generator's BNC. Using the settings you describe, auto memory (and 24M points, altho i didn't get a screenshot for 24M) I get the same result, the waveforms appear symmetric no matter what i do.

Since you're getting different results with the different probe setting, the probe being the problem might be the case? have you tried different probes or a BNC cable?

But yeah, if the probe isn't the problem, i would ask for a replacement
 

Offline Bud

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Some of you have attached screenshots in which the probe was set to 1X. But noise is lower in such case and test meander and ramp signals looks more symmetrical on my Rigol (see my screenshots). Please see how test meander will look if the probe is switched to 10X.
You should compare using same type of coupling. In your last set of screenshots you used different coupling (AC/DC) for x1 and x10 screenshots.
Facebook-free life and Rigol-free shack.
 

Offline Someone

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    • send complaints here
 

Offline BorisSSTopic starter

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Since you're getting different results with the different probe setting, the probe being the problem might be the case? have you tried different probes or a BNC cable?
The reason is not in probes definitely. Attached screenshots were taken with nothing connected to the inputs.

You should compare using same type of coupling. In your last set of screenshots you used different coupling (AC/DC) for x1 and x10 screenshots.
Pls believe me that the DC or AC Coupling mode has absolutely no effect on the waveform, so I will not redo this set of screenshots. I've already wasted too much time((

Thanks to all of you! You've convinced me that my device is faulty. I will try to exchange it for a good one if I can negotiate with the seller.
 

Offline Fungus

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Thanks to all of you! You've convinced me that my device is faulty. I will try to exchange it for a good one if I can negotiate with the seller.

If a flat line changes thickness just by moving it up/down the screen then something is broken.

PS: Does it do it on all channels?
 

Offline BorisSSTopic starter

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If a flat line changes thickness just by moving it up/down the screen then something is broken.
PS: Does it do it on all channels?
Yes in all channels.
I found one more unlucky man on the web with the same defect. It seems that my case is not an exception((
« Last Edit: April 12, 2023, 06:37:16 am by BorisSS »
 

Offline BorisSSTopic starter

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Thanks 2 all
As a result, after lengthy negotiations, the seller made an exchange for an oscilloscope for me, in which this defect is practically not visible.
PS: But be informed pls I am not the one only who bought Rigol DS1054 with such a defect.
 
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