Systems and methods to determine whether a brake is dragging based on post-takeoff spindown data are provided. Furthermore a method to operate such a binary logic unit is described. This allows wafer surface height for each side of the wafer, thickness variation map, surface nanotopography, shape, flatness, and edge map to be determined with a dual-sided fringe acquisition process. A circuit provides dynamic adjustment of the filter gains. 5 g, the dried coating comprises about 0.