Thank you for your detailed description. I wonder what kind of phase detector you are using. I have never heard of one that required 0.01Hz phase offset to lock. Even the simplest Phase-Frequency Detector (PFD) would do orders of magnitude better. Here are some papers: 1. Motorola App. Note AN-535 Phase-Locked Loop Design Fundamentals - the original mother lode on phase-frequency detectors - does not discuss deadband - I corrected this problem in my patent US3810234A https://www.nxp.com/files-static/rf_if/doc/app_note/AN535.pdf 2. HCT4046A phase-locked loop (PLL) Appendix B on Page 42: Loop Parameters and Equations Appendix C on Page 45: Basic Program for VCO Frequency Calculations https://www.ti.com/lit/an/scha003b/scha003b.pdf 3. Motorola MCK12140 Phase-Frequency Detector description https://pdf.dzsc.com/MCH/MCH12140.pdf 4. I prefer the filter network shown at the bottom of Table 2 on Page 4: Integrator Lead/lag network https://www.minicircuits.com/app/VCO15-10.pdf 5. You mentioned the difficulty in getting a low enough noise floor to measure the noise floor of the DOCXO. Rubiola has a nice paper on cross-correlation techniques that can easily add 20 dB to your measurement range: https://arxiv.org/pdf/1003.0113.pdf He shows some circuits in Figure 14 on Page 25: Basics schemes for the measurement of phase noise. Hope this helps.

Mike, The phase detector is an ADE-1 mixer, the IF output of the mixer goes into a loop filter that has a corner frequency of about 0.2Hz to enable Phase noise measurements down to 1Hz offset Thanks for the excellent references, a lot to study. Yes, one can do very advanced cross correlation things but I am doing this for a hobby and just needed something to check if the phase noise of some oscillators was good enough and could be build in a couple of hours using point to point wiring and a perforated board so I tried the least complex Phase Noise analyzer I could think of. Erik. On 4-7-2022 15:49, Mike Monett via time-nuts wrote: > Thank you for your detailed description. I wonder what kind of phase > detector you are using. I have never heard of one that required 0.01Hz > phase offset to lock. Even the simplest Phase-Frequency Detector (PFD) > would do orders of magnitude better. Here are some papers: > > 1. Motorola App. Note AN-535 > Phase-Locked Loop Design Fundamentals > - the original mother lode on phase-frequency detectors > - does not discuss deadband > - I corrected this problem in my patent US3810234A > https://www.nxp.com/files-static/rf_if/doc/app_note/AN535.pdf > > 2. HCT4046A phase-locked loop (PLL) > Appendix B on Page 42: Loop Parameters and Equations > Appendix C on Page 45: Basic Program for VCO Frequency Calculations > https://www.ti.com/lit/an/scha003b/scha003b.pdf > > 3. Motorola MCK12140 Phase-Frequency Detector description > https://pdf.dzsc.com/MCH/MCH12140.pdf > > 4. I prefer the filter network shown at the bottom of > Table 2 on Page 4: Integrator Lead/lag network > https://www.minicircuits.com/app/VCO15-10.pdf > > 5. You mentioned the difficulty in getting a low enough noise floor > to measure the noise floor of the DOCXO. Rubiola has a nice paper on > cross-correlation techniques that can easily add 20 dB to your measurement > range: > https://arxiv.org/pdf/1003.0113.pdf > > He shows some circuits in Figure 14 on Page 25: Basics schemes for the > measurement of phase noise. > > Hope this helps. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com