Marc, Nutsinee
First image from the SR785 is what we have (Q=0.3), the last image was what we first came up with (Q=1). Marc ended up having to short R2 (the 50 Ohms) for it to work somehow.... Haven't looked at the new LO transfer function but I was able to push the gain further before PZT rung up. Good for now. We didn't use LLO's design since out LO PZT doesn't have 29kHz resonance.