Phase Extractor

Extract the unwrapped phase of a complex input

• 

Libraries:
DSP System Toolbox / Signal Operations

Description

The Phase Extractor block extracts the unwrapped phase of a complex input.

Examples

Extract the Phase of Sine Wave

Use the Phase Extractor block to extract the phase of a sine wave signal.

• Open Model

Ports

Input

Input 1 — Input signal

vector | matrix

Specify the input signal as a vector or a matrix. When the input is a matrix, the block treats each column of the signal as an independent channel. The first dimension is the length of the channel. The second dimension is the number of channels. The block treats one dimensional inputs as one channel.

Data Types: single | double
Complex Number Support: Yes

Output

Output 1 — Unwrapped phase

vector | matrix

The block returns the unwrapped phase of the signal.

The block preserves the input size and dimension, and the output port rate equals the input port rate.

Data Types: single | double

Parameters

Unwrap phase only within the frame — Unwrap phase only within the frame

off (default) | on

When you clear this check box, the block ignores boundaries between the input frames. When you select this check box, the block treats each frame of input data independently, and resets the initial phase value for each new input frame.

Simulate using — Type of simulation to run

Interpreted execution (default) | Code generation

Specify the type of simulation to run. You can set this parameter to:

• Interpreted execution –– Simulate model using the MATLAB^® interpreter. This option shortens startup time.

• Code generation –– Simulate model using generated C code. The first time you run a simulation, Simulink^® generates C code for the block. The C code is reused for subsequent simulations as long as the model does not change. This option requires additional startup time but provides faster subsequent simulations.

Block Characteristics

Data Types	double | single
Direct Feedthrough	no
Multidimensional Signals	no
Variable-Size Signals	yes
Zero-Crossing Detection	no

Algorithms

Consider an input frame of length N:

$$\left(\begin{array}{l}{x}_1\\ x_2\\ ⋮\\ x_N\end{array}\right)$$

The step method acts on this frame and produces this output:

$$\left(\begin{array}{l}{\Phi }_1\\ {\Phi }_2\\ ⋮\\ {\Phi }_N\end{array}\right)$$

where:

$${\Phi }_i={\Phi }_{i-1}+\text{angle}(x_{i-1}^{*}{x}_i)$$

Here, i runs from 1 to N. The angle function returns the phase angle in radians.

If the input signal consists of multiple frames:

• If you set TreatFramesIndependently to true, the step method treats each frame independently. Therefore, in each frame, the step method calculates the phase using the preceding formula where:

  • $${\Phi }_0$$ is 0.

  • $$x_0$$ is 1.

• If you set TreatFramesIndependently to false, the step method ignores boundaries between frames. Therefore, in each frame, the step method calculates the phase using the preceding formula where:

  • $${\Phi }_0$$ is the last unwrapped phase from the previous frame.

  • $$x_0$$ is the last sample from the previous frame.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2014b

R2024a: Change in the default value of Simulate using parameter

The default value of the Simulate using parameter is now Interpreted execution. With this change, the block uses the MATLAB interpreter for simulation by default.