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dsp.PhaseUnwrapper System object

Unwrap signal phase


The PhaseUnwrapper object unwraps the signal phase input specified in radians.

To unwrap the signal phase input:

  1. Define and set up your System object™. See Construction.

  2. Call step to unwrap the signal phase according to the properties of dsp.PhaseUnwrapper. The behavior of step is specific to each object in the toolbox.


Starting in R2016b, instead of using the step method to perform the operation defined by the System object, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.


phUnwrap = dsp.PhaseUnwrapper returns a System object, phUnwrap. This System object adds or subtracts appropriate multiples of 2πto each input element to remove phase discontinuities (unwrap).

phUnwrap = dsp.PhaseUnwrapper('PropertyName',PropertyValue,...) returns an unwrapped System object, phUnwrap, with each specified property set to the specified value.



Enable unwrapping of phase discontinuities between successive frames

Set this property to false to unwrap phase discontinuities only within the frame. Set this property to true to also unwrap phase discontinuities between successive frames. The default is true.


Jump size as true phase discontinuity

Specify the jump size that the phase unwrapper recognizes as a true phase discontinuity. The default is set to π (rather than a smaller value) to avoid altering legitimate signal features. To increase the phase wrapper sensitivity, set the Tolerance property to a value slightly less than π.


resetReset internal states of Phase Unwrapper System object
stepUnwrap input phase signal input
Common to All System Objects

Create System object with same property values


Expected number of inputs to a System object


Expected number of outputs of a System object


Check locked states of a System object (logical)


Allow System object property value changes


expand all

Note: This example runs only in R2016b or later. If you are using an earlier release, replace each call to the function with the equivalent step syntax. For example, myObject(x) becomes step(myObject,x).

phUnwrap = dsp.PhaseUnwrapper;
p = [0 2/5 4/5 -4/5 -2/5 0 2/5 4/5 -4/5 -2/5 0 2/5 ...
    4/5 -4/5, -2/5]*pi;
y = phUnwrap(p');
figure,stem(p); hold
Current plot held
stem(y, 'r');
legend('Input (blue)','Unwrapped data (red)');
hold off;


This object implements the algorithm, inputs, and outputs described on the Unwrap block reference page. The object properties correspond to the Simulink® block parameters.

Extended Capabilities

See Also

Introduced in R2012a

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