Here's an image showing a big problem with sweeping with the Hantek.
The image shows the frequency change point from 200Hz to 300Hz - but because the frequency doesn't change at the zero-crossing of the waveform, you get a spurious frequency injected - in this case, it happens to be ~287Hz - as shown in the cursor measurement window.
Edit: BTW, I was incorrect in what I posted in a previous message. I did some more testing and it turns out that the Hantek software isn't capable of doing smooth sweeps either. Honestly, with the various problems inherent in the device (no zero-crossing of frequency change, no sync signal for sweep, etc, etc) I really don't think it's a good thing to use for sweeping - especially above 5MHz - but perfectly fine for basic signals and simple arbitrary patterns.