I'm working on Simulink model to calculate PMC's open loop gain. For now, all the parameters for frequency discriminator are copied from linfss6.m.

I'll work on correcting those parameters later.

The simulink model will allow us to learn how external noise will look like in our system.

The bode plot for PMC's TF is plotted in fig1.

I'm not sure why the measurement on both magnitude and phase looks bad at low frequency (f<10 Hz).

I think the model (fig2) is not correct because of the wrong units ( angular frequency,w, to frequency, f.) I'll check  this again.

The phase part seem to be completely wrong.

The parameters, (for example, cavitiy pole, frequency discriminator) for  the TF are not confirmed yet. I'll elog them once I verify them.

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Yesterday, I had a chance to test U6(OPA 27) in the schematic.The measurement agrees very well with the computed result, see fig 3.

The signal from source out was sent through FP2 test. TP2 and TP4 were connected to channel A and B on SR785 respectively.

SR785 was set to swept sine mode, frequency span from 1Hz to 10^5 Hz.

So we know that at least one part of the servo works properly.