Generate sine wave with increasing frequency
Simulink / Sources
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 1D check box. If you select this check box and the parameters are row or column vectors, the block outputs a vector (1D array) signal.
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 Types 

Direct Feedthrough 

Multidimensional Signals 

VariableSize Signals 

ZeroCrossing Detection 
