Products > Test Equipment
Rigol HDO1000 and HDO4000 12bit oscilloscopes launched in China
skander36:
--- Quote from: 2N3055 on January 30, 2023, 06:48:10 pm ---
--- Quote from: skander36 on January 30, 2023, 06:35:41 pm ---
--- Quote from: 2N3055 on January 30, 2023, 06:24:07 pm ---
Also it is obvious that user had great problems not being able to actual set FFT parameters effectively.
That is why there were dozens of posts...
--- End quote ---
If you are talking about me, I remember that I set the parameters as requested. This is why I request a specific setup.
If it was after me I can present a nice looking FFT and say : "Look how good it is!"
--- End quote ---
Problem is that scope does not let you set these parameters the way FFT should be set.
Also you say problem is only with 10kpts or less..
But that is a big problem, because number of points shouldn't matter. FFT is routinely done on 1024 or 512 points for that matter..
Scope at one point shows both 200 ksps/s and 400ksps for FFT and shows wrong data. No setting should produce that. Where do you set FFT points ?? Is there a setting for that?
--- End quote ---
If you are suggesting that there are too few setting available, I agree with you, but this setup case was a particular one, with two tone combined, that revealed some limits on this aspect.
Rigol could make more settings available to the user.
Fungus:
--- Quote from: mawyatt on January 30, 2023, 06:11:13 pm ---
--- Quote from: Fungus on January 30, 2023, 05:48:45 pm ---You mean simply display nothing on screen above that frequency?
That's a good question. Logic says "yes"... but it would look weird
--- End quote ---
Note, it does not display anything past 125KHz, immediately conveying to the user that this is "forbidden Nyquist frequency zone", and FFT display is not to be trusted!!
--- End quote ---
Cool!
(So Rigol's "fix" is easy... :popcorn: )
Fungus:
--- Quote from: 2N3055 on January 30, 2023, 06:24:07 pm ---Of course mirroring is a thing. You didn't say that. You said spectral leakage...Which is not same.
--- End quote ---
It's been a while since I studied this. I got my terms mixed up. Sue me.
--- Quote from: 2N3055 on January 30, 2023, 06:24:07 pm ---That is why I said you should stay out of this discussion. You are just repeating some terms you saw on internet without understanding.
--- End quote ---
Weird that none of the "experts" mentioned mirroring before I did.
Just sayin'...
skander36:
--- Quote from: 2N3055 on January 30, 2023, 06:56:12 pm ---
... If you put scope in Auto memory mode, it will have high enough sample rate and you won't see this..
--- End quote ---
This is one of the problems, my scope was in AUTO memory mode, as i said I use most of the time auto setting, but maybe this is not a good habit. You should pay attention all the time at this parameter as it can change over a lower limit. The automatic memory management is not so reliable and in some cases, like this, it will not allocate the correct memory back to the necessary number.
2N3055:
--- Quote from: Fungus on January 30, 2023, 07:09:32 pm ---
--- Quote from: 2N3055 on January 30, 2023, 06:24:07 pm ---Of course mirroring is a thing. You didn't say that. You said spectral leakage...Which is not same.
--- End quote ---
It's been a while since I studied this. I got my terms mixed up. Sue me.
--- Quote from: 2N3055 on January 30, 2023, 06:24:07 pm ---That is why I said you should stay out of this discussion. You are just repeating some terms you saw on internet without understanding.
--- End quote ---
Weird that none of the "experts" mentioned mirroring before I did.
Just sayin'...
--- End quote ---
No, don't be sorry. It is OK. Honest mistake is honest mistake.. it is grand of you to admit. Kudos!
Actually aliasing was mentioned several times. It includes "mirroring" or "folding" or downsampling... But I agree, it has been long and protracted over few pages.. again, easy not to connect...
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