%% Gain and Phase Variations Corresponding to Given Disk Size
% Determine disk-based gain and phase variations captured by a disk with size α = 0.5.

alpha = 0.5;
[GM,PM] = dm2gm(alpha)

% When you omit E, the dm2gm command returns the gain and phase variations corresponding to α with zero eccentricity. Zero eccentricity means that the disk represents gain that can increase or decrease by the same amount. In this case, α = 0.5 models a gain that can increase or decrease by up to a factor 1.6667 of its nominal value. The phase variation corresponding to this disk-based gain variation is ±28°. Visualize this disk.

diskmarginplot(alpha,0,'disk')

% The plot shows the values of F in complex plane corresponding to disk size alpha = 0.5 and E = 0. You can see that DGM = [1/GM,GM] for this disk.
% Copyright 2019 The MathWorks, Inc.