# Documentation

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# dsp.PhaseUnwrapper System object

Package: dsp

Unwrap signal phase

## Description

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.

 Note:   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.

## Construction

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

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

## Properties

 InterFrameUnwrap 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. Tolerance 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 $\pi$ (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 $\pi$.

## Methods

 clone Create phase unwrapper object with same property values getNumInputs Number of expected inputs to the step method getNumOutputs Number of outputs of the step method isLocked Locked status for input attributes and nontunable properties release Allow property value and input characteristics changes reset Reset internal states of Phase Unwrapper System object step Unwrap input phase signal input

## Examples

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).

hunwrap = 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 = hunwrap(p');
figure,stem(p); hold
stem(y, 'r');
legend('Input (blue)','Unwrapped data (red)');
hold off;
Current plot held

## Algorithms

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