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| REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol |
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| Xyphro:
Thanks, Teneyes, lucky to see that you also have blank lines. That there are blank lines is not really an issue, I think we are all on the same level of understanding. The ADC generates 256 steps and the display is 480 pixels high (minus some pixels for top and bottom bar). The procedure which lies between sample data and display data reshapes the data (interpolation / Decimation / ...) and pixels might not translate back 1:1 to ADC values, so depending on the level of interpolation/decimation, in between values can be shown on the display. But it is funny to see that this lead to the discovery that the 500uV mode is in fact no "true" 500uV mode and only a digitally scaled 1mV version. They could also offer a 250uV or 125uV setting with this method. |
| marmad:
--- Quote from: Xyphro on July 08, 2013, 08:33:14 am ---But it is funny to see that this lead to the discovery that the 500uV mode is in fact no "true" 500uV mode and only a digitally scaled 1mV version. They could also offer a 250uV or 125uV setting with this method. --- End quote --- While it's completely possible that 500uV is scaled from 1mV, I don't understand why Rigol wouldn't list this in the specs - just as Agilent does for the X-Series: "** 1 mV/div and 2 mV/div is a magnification of 4 mV/div setting." But since I don't have a clue as to how the Rigol handles gain at that setting, I'm afraid you just counting discrete values of different files is not, for me, definitive proof - just as you posting that the LSB of display memory data was always 0 wasn't definitive proof either. I'll admit that the evidence seems to point in that direction - but since I'm certain Rigol won't lie about the specifications, I'll wait to hear what their response is before I assume that this is fact. |
| Xyphro:
@marmad: It can still be a problem of the CSV data export within the scope, but if this would not be the case, I have no another explanation for the same amount of values in histogram. It's also a question if not mentioning something is really lying... I did another test by setting the amplitude of my signal generator to a value that I just get clipping in the values of the CSV file @ 1mV/DIV setting. When capturing at 500uV/DIV I get the same amount of clipping. What would be a proof for you? |
| marmad:
--- Quote from: Xyphro on July 08, 2013, 09:58:06 am ---@marmad: It can still be a problem of the CSV data export within the scope, but if this would not be the case, I have no another explanation for the same amount of values in histogram. It's also a question if not mentioning something is really lying :-) --- End quote --- Well, it probably can't be technically classified as lying ;) - but Rigol (as opposed to other Chinese manufacturers) has always seemed to be straightforward with their specifications; following accepted practices. If you look around at specs of DSOs which use scaling for lower vertical settings, I think it's a generally accepted practice to make a note of it in the specs. I've also emailed my dealer about it. He's an expert Rigol technician - so either he'll know, or he'll get the answer from Rigol. --- Quote from: Xyphro on July 08, 2013, 09:58:06 am ---What would be a proof for you? --- End quote --- Well, I assume you're probably right - but I want to hear Rigol's response. I'm sure they won't lie about it when asked - since it could cause trouble for them if they did. |
| Teneyes:
--- Quote from: Xyphro on July 08, 2013, 08:33:14 am ---The procedure which lies between sample data and display data reshapes the data (interpolation / Decimation / ...) and pixels might not translate back 1:1 to ADC values, so depending on the level of interpolation/decimation, in between values can be shown on the display. --- End quote --- Yes , The DSO can interpolate extra data point between 7 Bit data samples to create data values for the Display. But, I wonder why I see 8 bits in the Waveform data file witch is before the display program handler |
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