Boundary of the continuous spectrum

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The continuous spectrum of a $\mathcal{QT}$ matrix $A$ is given by the image of the unit circle through $a(z)$, the symbol, and the part of the complex plane that have winding number different from zero.

Contents

Syntax

R = range(A) returns a sampling of points obtained by evaluating the symbol of $A$ at points on the unit circle.

Example

E = [ zeros(3, 7) , diag([ 8, -8, 8 ]) ];
A = cqt([0 1 -2 1], [0 1 1 0 -1 0 0 1], E);

plot(range(A));