Here is a patent filed by Boeing
The present invention is directed to a non-normalized aircraft angle-of-attack indicating system. An angle-of-attack vane produces a signal α' indicative of raw aircraft angle-of-attack. A pitot-static system (68) produces output signals representative of aircraft static pressure and total pressure, Ps and Pt, respectively. The signals α', Ps and Pt are fed to an air data computer (66) which correspondingly produces an aircraft actual angle-of-attack value α and a calculated Mach number, M. Configuration sensors (80) produce output signals representative of gear position, g, flap position, f, and speed brake position, sb. The signals α, M, g, f and sb are fed to a display computer (76). The display computer includes a submodule (90) which utilizes a lookup table to determine a value of angle-of-attack stick shaker, αss from the values of M, g, f and sb. A second submodule (92) utilizes a lookup table to produce a second angle-of-attack reference value αref from the values g, f and sb. The display computer (76) feeds the α, αss, αref signals to an angle-of-attack indicator which includes a pointer (102) which is moveable with respect to a fixed gauge (104). The α signal is used to drive the pointer (102) to indicate the aircraft's actual angle-of-attack. Bug drivers are utilized to position the first bug αss and the second bug, αref, at their appropriate positions on the opposite side of the gauge.
Aircraft non-normalized angle-of-attack indicating system - Patent 6131055
A fuller explanation may be found at
Aircraft non-normalized angle-of-attack indicating system - US Patent 6131055 Description