Products > Test Equipment
REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
EV:
Yes, Sin(x)/X interpolation is outside the linear path. This can not be the correct way to do the algoritm. This is probably problem only with fast rising pulses and short time bases. It works however fine if only one channel is on. It is enough for me.
--- Quote from: Teneyes on December 29, 2013, 01:26:43 pm --- @ EV note that with 2CH there are less samples so the Sin(x)/X interpolation will make the curve go off the linear path
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marmad:
--- Quote from: EV on December 29, 2013, 02:05:55 pm ---Yes, Sin(x)/X interpolation is outside the linear path.
--- End quote ---
Sin(x)/x is NOT a linear path - lots of information you can read about it online. ;)
"Unlike the narrow pointed triangle of linear interpolation, the window for SinX interpolation is a theoretically never ending damped sinewave. "
EV:
OK, maybe it works correctly, but there are too few sample points for this fast rising pulse. Thanks for the picture! I am very lazy to read manuals and any other information. ;) ;D
--- Quote from: marmad on December 29, 2013, 02:10:35 pm ---Sin(x)/x is NOT a linear path - lots of information you can read about it online. ;)
"Unlike the narrow pointed triangle of linear interpolation, the window for SinX interpolation is a theoretically never ending damped sinewave. "
--- End quote ---
EV:
Here is for comparison the picture with same traces from my old TEK TDS3032. It is 300 MHz scope but the measured BW is over 400 MHz and it has 5 points per division as I told before.
marmad:
--- Quote from: EV on December 29, 2013, 02:28:03 pm ---OK, maybe it works correctly, but there are too few sample points for this fast rising pulse. Thanks for the picture! I am very lazy to read manuals and any other information. ;) ;D
--- End quote ---
;D
Well, the main thing to remember is that sin(x)/x is susceptible to errors if the original signal contains frequencies higher than the Nyquist frequency. At 1GSa/s (maximum with 2 channels on), that happens to be 500MHz. With the 300MHz enabled on a DS2000 HW v.1 model, 500MHz is around -12dB (according to Wim's chart) - so if you have questions about interpolation errors, you might also try it with the 100MHz BW filter on.
--- Quote from: EV on December 29, 2013, 02:45:25 pm ---Here is for comparison the picture with same traces from my old TEK TDS3032. It is 300 MHz scope but the measured BW is over 400 MHz and it has 5 points per division as I told before.
--- End quote ---
Yes, I think your TDS3032 might be a TDS3052 by mistake ;) If your sampling rate is 5GSa/s, then the Nyquist frequency is 2GHz.
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