Having added the attenuator, A(s), at the input A of the LB1005 the loop algebra is changed slightly: Attachment 3 has the algebra and Attachment 4 helps with understanding the symbols. I have just considered this attenuator separately from the plant and servo.

Attachment 1: Open Loop TFs

• The yellow curve is the actual open loop transfer function after subtracting 5dB in the magnitude of the ratio between the PDH error signal and the LB error signal to compensate for the 10dB attenuator at the input A of the LB box
• The blue and orange magnitude curves were recorded directly from the Moku
• The phase of the Math channel saved from the Moku seems to be a copy of the magnitude for all three OLTFs even though the screenshots seem to show a real phase (the data for this is saved in Attachment 3 and shown in the previous elog) so I re-calculated the phase but I'm not sure if it fully makes sense. (The calculation is in Attachment 4)

Attachment 2 is all the individual closed loop transfer functions that were recorded to calculate the open loop ones.

Attachment 3 has the data, settings, and screenshots recorded from the Moku to calculate OLTFs

Attachment 4 is the Jupyter notebook used to generate Attachments 1 and 2

Attachment 5 has the loop algebra and diagram

Attachment 6 is a diagram of the setup depicting the loop components

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import matplotlib as mpl, matplotlib.pyplot as plt\n",