Simulink^® Control Design™ lets you measure the frequency response of your system in operation. The block performs an experiment that injects signals into the plant and measures the plant output. If you have a code-generation product such as Simulink Coder™, you can generate code that implements the estimation algorithm on hardware. Deploying the algorithm to hardware lets you measure the frequency response of a physical plant in real time. To get started, see Online Frequency Response Estimation Basics.