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Unwrap Signal

This example uses:

Open Script

This example shows how to use the Unwrap block to unwrap a 3-by-2-by-3 array that has discontinuity.

Each 3-by-2 frame of the signal has a discontinuity. In the first frame, there is a discontinuity between the second and the third element greater than the tolerance of $\pi$ set in the block parameters. In the second frame, the discontinuity between the second and third element is less than $\pi$, and in the third frame, the discontinuity is equal to $\pi$. Since we expect the block to wrap signals with discontinuities greater than the tolerance, unwrapping the signal does not affect the second or third frame.

Open the Simulink model.

model = "ex_unwrap";
open_system(model);
frame1 = [0 0; 2*(pi)/3 0; -2*(pi)/3 0];
frame2 = [2*pi 0; 8*pi/3 0; 9.5*pi/3 0];
frame3 = [4*pi 0; 13*pi/3 0; 16*pi/3 0];
signal = cat(3,frame1,frame2,frame3)

signal(:,:,1) =

         0         0
    2.0944         0
   -2.0944         0


signal(:,:,2) =

    6.2832         0
    8.3776         0
    9.9484         0


signal(:,:,3) =

   12.5664         0
   13.6136         0
   16.7552         0

The Tolerance parameter of the Unwrap block is set to $\pi$. The block therefore unwraps discontinuities which are larger than $\pi$.

Run the model.

output = sim(model);

See that the output, output.unwrapped_signal does not have the first discontinuity, but the other two remain.

output.unwrapped_output

ans =

         0         0
    2.0944         0
    4.1888         0
    6.2832         0
    8.3776         0
    9.9484         0
   12.5664         0
   13.6136         0
   16.7552         0

See Also

Blocks