Products > Test Equipment
REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
marmad:
--- Quote from: evanh on November 20, 2013, 10:55:08 am ---It is a prerequisite for high-res acquisition.
--- End quote ---
When you use the term "oversampling", what exactly are you referring to? Do you mean a sample rate higher than what is normally used at a given time base (which would be the normal definition in this context)? If so, as already pointed out (and ignored by you), the normal sample rate of the Agilent @ 5us/div is 2GSa/s.
So what happens when you turn on High Res at that time base? Does the Agilent start sampling faster than 2GSa/s? Of course not - it can't! All it does is start adding the incoming samples together - so it's not sampling "over" (above) the given rate; it's just trading off bandwidth for 'effective' resolution. This is exactly what the Rigol (DS2000) does when set to 5us/div @ 2GSa/s - it just saves the samples first before adding them together later.
So in your mind, in this example - are they both "oversampling" - or is neither? They are both sampling @ 2GSa/s and combining the acquired samples.
--- Quote ---I've never said otherwise. The only comment I've made is that the maths is not the issue. The real issue is the lack of oversampling and the filtering cutting into the displayed trace.
--- End quote ---
;D Seriously? Wow, you must be the most stubborn person on this forum (which is saying a lot). You wrote several assertions which have already been proven incorrect with data- such as:
--- Quote from: evanh on November 18, 2013, 12:45:06 pm ---....and what's more (Rigol) doesn't even say how severe this filter is let alone have any parameters.
--- End quote ---
Well, ignoring the fact that Agilent ALSO doesn't say how severe their filter is: Yes, there ARE parameters; they follow the basic filter formula for successive sample averaging; and they are quite predictable.
--- Quote from: evanh on November 18, 2013, 12:45:06 pm ---...(Agilent) need not create any extra filtering beyond the stored sample rate ... and probably ensures it never does by adjusting the bit depth accordingly.
--- End quote ---
It's obvious from the real data that Svuppe and I posted that the filtering is quite similar between the Agilent 2000X and Rigol DS2000 - with the tables shifted based on the decision by each DSO manufacturer as to which time base to use when implementing 12-bit averaging.
--- Quote from: evanh on November 18, 2013, 12:45:06 pm ---That's the difference (between Agilent and Rigol) and it's significant.
--- End quote ---
NO - you were wrong: the difference is NOT significant. Ignore or deny it all you want (and having interacted with you before - I'm guessing you will), but I'm confident it's clear to anyone else reading these posts.
EDIT: Yep - as predicted: ignored ;D
Svuppe:
I don't believe there is anything called auto memory. At least I haven't found it yet.
Carrington:
--- Quote from: Svuppe on November 20, 2013, 02:43:58 pm ---I don't believe there is anything called auto memory. At least I haven't found it yet.
--- End quote ---
:) Ok.
The DS2K auto set the memory according with the base time.
Time/Div Auto Menory (One channel)
1ks 14M
...
500us 14M
200us 5M6
100us 2M8
50us 1M4
20us 560K
10us 280K
5us 140K
2us 56K
1us 28K
500ns 14K
200ns 5K6
100ns 2K8
50ns 1K4
20ns 700
10ns 700
5ns 700
marmad:
The High Res BW table I made for the DS2000 is really rather crude - I just don't own a decent FG/AWG, so many of the values are approximations.
@Teneyes: Perhaps you can run the sweep tests again using a decent FG/AWG)? I think you have a DG4000 series, right? ;)
Just make sure you test with memory depth set to 14MB or AUTO!
Carrington:
I only have a digital pattern generator from my omega logic analyzer, so I can't do it.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version