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Products => Test Equipment => Topic started by: andow on May 09, 2022, 08:50:19 pm

Title: Siglent SDS2104X Plus FFT
Post by: andow on May 09, 2022, 08:50:19 pm
Hello everybody! I've been lurking this forum for a long time, finally here is my first post!  :)

I recently bought a Siglent SDS2104X Plus and am really happy with it so far. One thing that puzzles me however is the display of the FFT (see attachment for an example).

- First of all the x-axis is always linear, is there really no way to make it logarithmic?
- My main use for the oscilloscope is testing audio equipment. When analyzing the frequency range of 20Hz-20kHz the essential area nearly up to 2kHz is covered by the y-axis scale. Is there a way to change this so the graph starts to the right of the scale?
Title: Re: Siglent SDS2104X Plus FFT
Post by: Martin72 on May 09, 2022, 08:55:02 pm
Quote
When analyzing the frequency range of 20Hz-20kHz the essential area nearly up to 2kHz is covered by the y-axis scale. Is there a way to change this so the graph starts to the right of the scale?

AFAIK no, maybe they can implement it as a additional feature in a future firmwareupdate.
The scaling itself is too much - Nobody needs 4 digits after the comma...IMHO a bug to fix.
Title: Re: Siglent SDS2104X Plus FFT
Post by: TheLaSwamp on May 09, 2022, 11:57:50 pm
Nice rig! I have the 1104X-U and I love it. It's it a bit lower in the food chain than yours, but I'm really enjoying tinkering with it.
Title: Re: Siglent SDS2104X Plus FFT
Post by: bdunham7 on May 10, 2022, 12:46:56 am
You can run two FFTs simultaneously.  Here is a 1kHz square wave with FFT1 at 0-20kHz and FFT2 at 0-2kHz.  Sort of like a zoom, adjust as needed.
Title: Re: Siglent SDS2104X Plus FFT
Post by: 2N3055 on May 10, 2022, 06:32:22 am
You can set to start from -100Hz .... Or any negative value. That will shift FFT curve to the right. ^-^
Or you can simply pull it to the right with the finger...
Or pinch zoom like on a tablet..
Title: Re: Siglent SDS2104X Plus FFT
Post by: andow on May 10, 2022, 08:58:08 pm
Thanks everybody for the replies! Some good tips here to make it more usable....

It would be great if Siglent would come up with an update for this feature. I know they have dedicated spectrum analyzers but I think it's such a waste since this feature is already there in the SDS2000X.

Anyway, still more than happy with this oscilloscope! Definitely a big upgrade from my old Philips.... ;D
Title: Re: Siglent SDS2104X Plus FFT
Post by: Martin72 on May 10, 2022, 09:14:48 pm
Absolutely... ;)

Me, I´ve bought a used Neutrik A1 audio analyzer system for audio purposes.
Because to judge over a DUT it takes a measure equipment which is definitely or mostly better than the DUT...


Title: Re: Siglent SDS2104X Plus FFT
Post by: 2N3055 on May 10, 2022, 09:58:24 pm
Thanks everybody for the replies! Some good tips here to make it more usable....

It would be great if Siglent would come up with an update for this feature. I know they have dedicated spectrum analyzers but I think it's such a waste since this feature is already there in the SDS2000X.

Anyway, still more than happy with this oscilloscope! Definitely a big upgrade from my old Philips.... ;D

You do know you have built in frequency response analyser in a scope? That does gain/phase plots and does it with log frequency too...?
Title: Re: Siglent SDS2104X Plus FFT
Post by: andow on May 11, 2022, 09:58:05 am
Absolutely... ;)

Me, I´ve bought a used Neutrik A1 audio analyzer system for audio purposes.
Because to judge over a DUT it takes a measure equipment which is definitely or mostly better than the DUT...

Sure, I know that there are better devices for this. We have a Rohde & Schwarz Audio Analyzer in the studio and I also often use my RME interface with REW for this.
But for a quick peek it's still nice to have on the oscilloscope.... ;-)


You do know you have built in frequency response analyser in a scope? That does gain/phase plots and does it with log frequency too...?

Yes I do ;-) And it's a very cool feature! But it takes time and you can't measure in "real time", so the FFT is good for a quick check.

But a Bode plot is really nice to have on the scope, and you don't even need an external function generator! I think this was the feature that sealed the deal for me buying the Siglent.