# Frequency Response Measurements

To achieve a good frequency response measurement, the frequency range of interest must contain a significant amount of stimulus energy. Two common signals used for frequency response measurements are the chirp signal and a broadband noise signal, such as white noise.

It is best not to use windows when analyzing frequency response signals. If you generate a chirp stimulus signal at the same rate you acquire the response, you can match the acquisition frame size to the length of the chirp. No window is generally the best choice for a broadband signal source. Because some stimulus signals are not constant in frequency across the time record, applying a window might obscure important portions of the transient response.