I think I will add another functionality that would be interesting for testing: the possibility to have a fixed output range. This will allow exploring the full output ranges at different frequencies, thus finding the best thresholds for switching the outputs.
This function will also be useful later on if you don't want relays switching during your tests.
I did at some point get annoyed when dialing up the frequency past 20MHz (I think 20 was the limit), and having the Vpp click down from 10Vpp to 5Vpp
It should not change the offset or amplitude just because you are changing frequency. Instead, refuse to set the new frequency.
On the other hand, if you want to go up to 30Mhz, and it is not letting you, it would be nice if it indicated why not. Maybe by flashing the amplitude inverted red every time you try to tick past 20MHz. Same if you try and up the amplitude and it will not let you: flash inverted red the frequency or limits.
This is not exactly what you asked about of course, but related and I was reminded of it.
As to locking the relays/range:
I noted that when you change frequency, the FPGA does that seamlessly. Not a single sample missed in the signal train, it even stays in phase, just at a higher frequency.
Except when it also changes range, then you loose signal for a few ms while it ticks over. So I can see a locked relay being useful sometimes.
A good idea will be to see if we can use the latest FPGA image for older devices, I'm wondering what had happen with the 3.4.1 firmware version, did anybody encountered it again ?
I think you mean 3.2.1. That was reported once, but I do not remember a 3.4.1
Its easy to experiment with that. We can flash the Winbond all we want. But no-one ever published 3.2