Products > Test Equipment
REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
marmad:
--- Quote from: Xyphro on July 06, 2013, 10:02:39 pm ---Are you sure?
I can also clearly see on the screen, that the signal is scaled. The steps are clearly visible and larger as compared to e.g. 1mV/DIV.
--- End quote ---
I'm not sure what that proves. Depending on the signal, the steps can be clearly visible - and look similar to what you posted - at any vertical setting. Rigol made a big deal advertising the 'true' 500uV setting of this DSO - and while there's many things I dislike about the company - I've never experienced them lying about their specifications.
As I mentioned, you're correct when you say the LSB is 0 when you read DISPLAY memory when set to the 500uV/div setting - but when you read SAMPLE memory, the LSB is 0 or 1 - I just tested it.
Teneyes:
--- Quote from: Xyphro on July 06, 2013, 09:08:01 pm ---Another thing I noticed - maybe already known and not a bug.
In 500uV/DIV mode, the scope is internally set to 1mV/DIV and the data scaled by a factor of 2. This can be noticed when reading out the waveform data. The LSB is always 0. This effectively reduces the ADC resolution by 1 bit / dynamic range.
--- End quote ---
@Xyphro
Did you test this on your DS2000?
What version of Firmware was this bug?
as a bug dealing with 500uV scale was fix in the latest firmware.
But with full scale being -2.5 mV to +2.5mV
and a noise floor of about 400uv un-filtered and Not Averaged I think 7 bit resolution is good
Below is a Sweep of 4-40MHZ at 5mVpp on the 500uV/div scale , the traces are noisy but Good
Xyphro:
The signal was an analog one and the slope is slow at some positions. I doubt it is the signal source being responsible for this discrete steps in this case.
So it looks they have a bug showing the trace correctly in 500uv/div setting in case the sample memory shows the correct lsb.
If the spec says true 500uv/div support it is actually wrong due to this bug, because the main purpose should be in most cases to look at the trace on the screen.
Xyphro:
It was the very latest firmware version which appeared just some days ago. Currently I'm not close to my scope, so I cannot check it now.
Xyphro:
I agree, it is not a serious issue :-)
Just a funny fact.
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