I ordered the X-parameter book, but have a few questions:
1) I realize I need true 2-tone X-parameter extraction to properly characterize IMD, and 1-tone extraction will get me AM-AM and AM-PM. Though AM-AM will contribute to IMD and cause spectral regrowth. So there seems to be a disconnect. There was a paper that showed IMD from 1-tone measurement, but the IMD3 fit was pretty poor. Should I be using two sets of X-parameters; one for IMD (predicting spurs in conversion chains), and another for EVM?
2) I'm using an external source to drive the comb generators. Is this really necessary (can I use the 10 MHz source) since I'll have to get another generator for the two-tone source?
3) What generator do you recommend for the two-tone source? One that has decent IMD performance using it's internal ARB. For now, I probably don't need to go past 6 GHz for the drive tones.
4) Will I be able to extract a single 2-tone X-parameters file over both swept frequency, power, and tone spacing?
Maybe this is covered in the book, but I figured I'd ask as I wait for it's arrival.