Very good analysis. Looking forward to reading more.
Disclosure: I am not an engineer...my experience is pilot based, mostly in the F-4. I also have 19 years experience in Aerospace, mostly in program management. I do have experience with glass cockpit aircraft.
I have absolutely no knowledge of Boeing's designs or data. The information to be presented is generic and is only for discussion purposes.
A computerized aircraft would have a "central" computer system with dual or triple redundancy. In the military, this computer is called the mission computer. I am not going to discuss how redundancy is achieved as there are several ways this can be done, all acceptable. The central computer gets data from on-board and off-board sensors through a data bus architecture...the data bus also contains redundancy.
The on-board sensors can be analog or digital. If they are analog, then there is some type of adapter tied to the sensor that converts the analog signal to digital and puts the data on the data bus. The central computer then analyzes all of the data and displays some of the data on the pilot's displays. It also sends data to other on-board computers, such as the FADECs (which control the engines) and the auto-flight system. Note: auto-flight could be stand alone or integrated into the central computer.
When analyzing the sensor data, the central computer is comparing inputs from like sensors (data from the pilot's AOA sensor is compared to the data from the co-pilot's AOA sensor). If the data agrees, then there is no problem. Problems arise when the data disagrees. If there is a disagreement, the central computer can calculate what the AOA should be, based on airspeed, g-loading, bank angle, pitch angle. Based on that calculation, the central computer can determine which AOA sensor is malfunctioning.
So...based on what logi_cal869 and I have read, the MCAS only uses one AOA sensor and does not interface directly with the central computer. In fact, the MCAS has authority over the central computer and can command the pitch trim system to lower the nose (reduce AOA), even if the central computer knows that the aircraft is nowhere near stall.
To me, this design in unbelievable.
I plan to add some more comments later...feel free to comment and ask questions.