I'm just looking to characterize fairly low frequency (~10MHz and less. Mainly audio stuff though) filters and amplifiers. I wish I could get an AWG at reasonable prices, but I'm a student, and Aliexpress is not
available to me anymore so the 60MHz cheapies aren't something I can buy.
As for the ADCs, if they're the only ways to get the phase difference, I'll go that way, but if not I'd like to go the mixer way. Makes things much cheaper. ADCs at that sampling rate basically require a very fast microcontroller or
an FPGA, either of which would balloon the budget. Again, if that's the only way to achieve my goal, I'll do it. On the other hand, if there's a cheaper way that works, I'd like to go that way.