I have an eval ADF4007 which I want to use to phase lock two lasers together. I'm testing it before getting to that feedback part, and I'm having an issue with error output from the CP/phase detector:
Setup: RF synthesizer for 6.8 MHz and another RF synthesizer for 106.8 MHz. Vtune out is going to an oscilloscope. Muxout going to a spectrum analyzer just to check. Also M2 and M1 are set to 1 and 0, respecticvely for "active" CP and Muxout at N divider output with a PFD polarity of +ve.
- This PLL is supposed to be comparing the REFin with the divided RFin, right?
- Is the Phase detector output the Vtune output of the board?
- When I change the phase of the 6.8 GHz input, shouldn't I be getting some change at the Vtune output? It is always at 0, regardless of what I change in the input signals.