Chirp Signal

Generate sine wave with increasing frequency




The Chirp Signal block generates a sine wave whose frequency increases at a linear rate with time. You can use this block for spectral analysis of nonlinear systems. The block generates a scalar or vector output.

The parameters, Initial frequency, Target time, and Frequency at target time, determine the block's output. You can specify any or all of these variables as scalars or arrays. All the parameters specified as arrays must have the same dimensions. The block expands scalar parameters to have the same dimensions as the array parameters. The block output has the same dimensions as the parameters unless you select the Interpret vector parameters as 1-D check box. If you select this check box and the parameters are row or column vectors, the block outputs a vector (1-D array) signal.

The following limitations apply to the Chirp Signal block:

  • The start time of the simulation must be 0. To confirm this value, go to the Solver pane in the Configuration Parameters dialog box and view the Start time field.

  • Suppose that you use a Chirp Signal block in an enabled subsystem. Whenever the subsystem is enabled, the block output matches what would appear if the subsystem were enabled throughout the simulation.

Data Type Support

The Chirp Signal block outputs a real-valued signal of type double.

For more information, see Data Types Supported by Simulink in the Simulink® documentation.


Initial frequency

The initial frequency of the signal, specified as a scalar or matrix value. The default is 0.1 Hz.

Target time

The time at which the frequency reaches the Frequency at target time parameter value, a scalar or matrix value. The frequency continues to change at the same rate after this time. The default is 100 seconds.

Frequency at target time

The frequency of the signal at the target time, a scalar or matrix value. The default is 1 Hz.

Interpret vector parameters as 1-D

If selected, column or row matrix values for the Initial frequency, Target time, and Frequency at target time parameters result in a vector output whose elements are the elements of the row or column. For more information, see Determining the Output Dimensions of Source Blocks in the Simulink documentation.


Data Types


Sample Time


Multidimensional Signals


Variable-Size Signals


Zero-Crossing Detection


Code Generation


Introduced before R2006a

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