31-01-2016, 10:36 AM
Yeah, saw that video when it came out a few days back...
I've yet to find a DSO with a useful FFT mode.
Don't forget that nearly all of them use an 8 bit ADC, so results will be limited by that.
There are a lot of parameters that go into performing an FFT, so there is scope (bad pun!) to tweak and optimise if wanted, but ultimately, the 8 bit conversion limits you to 48dB of dynamic range (unless you do oversampling or other tricks).
Essentially, it's a tick-box on the marketing sheet. Some manufacturers might put more effort into it - like R&S did for their model that was featured in that video - but for most, it's perfunctory at best.
Bear in mind that I come at this with an audio perspective, where I'm used to 90 to 100dB of separation between fundamental and harmonics. For this you need dedicated gear using 24 bit converters.
Also bear in mind that no conventional analogue scope does FFTs, so it would be churlish to be negative about a DSO because of its FFT behaviour, bearing in mind all the other functionality that you're getting with the DS1054Z for just £300!
If you need good FFT performance, you need a spectrum analyser or equivalent.
I've yet to find a DSO with a useful FFT mode.
Don't forget that nearly all of them use an 8 bit ADC, so results will be limited by that.
There are a lot of parameters that go into performing an FFT, so there is scope (bad pun!) to tweak and optimise if wanted, but ultimately, the 8 bit conversion limits you to 48dB of dynamic range (unless you do oversampling or other tricks).
Essentially, it's a tick-box on the marketing sheet. Some manufacturers might put more effort into it - like R&S did for their model that was featured in that video - but for most, it's perfunctory at best.
Bear in mind that I come at this with an audio perspective, where I'm used to 90 to 100dB of separation between fundamental and harmonics. For this you need dedicated gear using 24 bit converters.
Also bear in mind that no conventional analogue scope does FFTs, so it would be churlish to be negative about a DSO because of its FFT behaviour, bearing in mind all the other functionality that you're getting with the DS1054Z for just £300!
If you need good FFT performance, you need a spectrum analyser or equivalent.
