We made a model for the dither angular stabilization system c1ass.mdl. The attached file shows the diagram.

The idea is to dither a combination of 6 optics (ETMs, ITMs, PZTs) at different frequencies and demodulate three PDs (TRX, TRY, REFL11I). Then form the DOFs from demodulted signals, filter, and send each DOF to a combination of optics.

This is enough to get started with arm cavities alignment (we may need to add the BS for the Y arm). More optics and PD can be added as they become available and/or needed.

The DAC for the fast PZT  are not connected and have to be commissioned.