Slave piezo channel investigation
# plot 1 gives the TF of the Slow pzt.
PZT fast removed, gain 1/f, Pertub on 'analog in' channel. TF = Injection error signal / Vpzt (voltage on the pzt, not pztmonit)
# plot 2 gives the TF of the Fast pzt
PZT fast disconnected, gain 1/f, Gain reduced as much as possible to avoid that slow the Slow pzt eats the perturb sent on the Fast pzt. Perturb on PZT_fast input. TF = Injection error signal / Vpzt
# Plot 3 gives the extrapolated TF of PZT_fast and PZT_slow channels from M11 AmpOp input to the Error signal. M11 Amp Op input receives the voltage which is then split into Fast and slow PZT channels (factor x90 between the gain of both channels in the rampauto).
we see that there is a mismatch between both slow and fast channel. 10 dB gain are missing on the fast channel to be as efficient as the slw channel.
# Plot 4 gives the Error signal and superimposed te TF of the slw pzt
we see that the above 10k strctures are due to the Slow piezo.
Those structure should be eaten by the fast piezo which seems to have only a very weak correction.
--> it seems there is an un-balance between fast and slow pzt channels. Altough it has been already checked ( 44340 )
--> the perf are anway compliant
# Plot 5 is te OLTF of the injection loop.
with ATT_RF = 20 dB, PDH = 1,8 Vpp