If those are made on your PC from data pulled from scope, that is just funny.
We are arguing FFT implementation on a scope is half cooked, and to disprove me you post images of FFT that you made on PC because FFT on scope is crap...
What a great irony is that?
so you didnt see the picture of built-in FFT i posted?
312K FFT points (625Ksamples) i'm providing both i'm not sure what siglent marketing hype refering to "points"? do you have any better siglent screenshot FFT? you asked people to do you favor by providing screenshots, but you didnt provide anything yourself. people are having hard time understanding what you want. in any case, i was showing that FFT of DHO800 is much much better than previous DS1000Z. i initially thought this thread is comparing new rigol vs older rigol, but it turn out differently, re-reading OP, maybe he want to compare between rigol and siglent, but his rigol hasnt arrived yet? so lets wait, i hope its going to be a thorough one including pulling data to PC, i havent seen that be done with siglent scope and its code example.
and to the rest replying i dont have time quoting each one... my point was, raw 16bit data can be pulled to PC from Rigol DHO800 scope, can this be done with Siglent? if not, dont bother claiming it has better built-in FFT, because it crap anyway compared to proper SA. i also pointed out, with higher data point count, cleaner FFT can be achieved, i dont know your theoritical formula for X bit scope's noise floor, but FFT i've shown has cleaner floor at -120dB although there are some spurious below -90dB, we should be able to see low level signal existence in -60 to -80dB range, since spurious are below that, and where there are no spurious in freq domain, we can see signal of much lower level, too bad my rfgen can only go -40dBm output and not the high end pure sine one. we can safely say imho anything above -90dB are real signal to be analyzed. even built-in FFT above also showing -120dB floor, does FFT algorithm lies?. and its lower RBW too with more datapoints only can be achieved by pulling data out of Rigol to PC, i believe even the holy grail siglent built in FFT is "blobby" (leaky) due to large RBW. and through VISA driver API, i can automate it into program instead of copying it into CSV in pendrive and then play math in Excel or Matlab, that is tedious and slow work. from some stand, i can say any entry level dso's built in FFT are useless anyway, so there is not much point highlighting it. thats why i developed my own SW, even 1Mpts siglent is not enough for me. i was looking its programming guide i believe i have it stored somewhere, but i havent seen a working SW/code example. ymmv.
.. i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB..
How they do that -120 to -140dB dynamic range with a 12bit ADC?
PS: provided you mean the "noise floor" - how they could achieve such a low n.floor?
Some literature to scratch the surface...
https://www.edn.com/dsos-and-noise/
thats not literature... this is literature...
https://dsp.stackexchange.com/questions/86124/units-of-6-02n-1-76-as-an-fft-noise-floor and this
https://www.eetimes.com/fft-plots-provide-insight-to-a-d-performance/ but i wont bother digging deep. i already have 10Mpts FFT, with markers system and zoom out zoom in feature. so thats what i will use.. what you need to prove to me now is why FFT algorithm lies?