Frequency Response Using DSP instead of Swept Sine

This demonstration uses white noise to stimulate the unit under test. White noise contains energy at all frequencies, and by using the Fast Fourier
Transform we are also able to compute the response of the UUT at all frequencies simultaneously. This gives a significant speed advantage compared to the swept sine method where only one frequency is measured at a time.

Notice that the method is essentially instantaneous. Set the Frequency Resolution to 1 Hz. Now the measurement slows down by a factor of 10.

The Unit Under Test controls are locked in this experiment so you can compare it to the one using Swept Sine If you want to experiment freely with all controls, download the VI called Frequency Response and Phase using DSP method.vi.

For more information about the measurement of Frequency Response, search for Frequency Response in the Developer Zone.

Requirements

Filename: 3731.vi

Software Requirements

Application Software: LabVIEW Full Development System 6.1
Language(s): LabVIEW

Reader Comments | Submit a comment »

Hi I get "error 34" Vi has not been signed when I try to use it with the LabVIEW player
- Lars E Nyegaard, GN Netcom. lnyegaard@gnnetcom.com - Dec 8, 2005