Detecting Harmonics

This procedure consists of identifying and detecting frequencies that are multiples of a fundamental frequency, which is the first line of a sound, that is to say the lower frequency around zero Hertz.

To Detect Harmonics:

Prerequisites: You need to open or calculate a time frequency representation. You need to adjust the time-frequency window. The better the representation, the better the detection will be.

In the toolbar, click Detect harmonics .
The RPM Detection dialog is displayed and the harmonics selection tool is enabled.
In the representation, click several points on one harmonic from the start of the signal (0 second) to end of the signal.

Several points are selected on the harmonic.
In the Detect harmonics window, set the:
- number of selected harmonic from the Select harmonic field.
- thickness of an area around the selected harmonic from the Search width field.
- smoothness of the curve from the Regularity field.
- rank (or number) of the first harmonic to be detected from the First harmonic field.
- rank of the last harmonic to be detected from the Last harmonic field.
- step between two harmonics from the Harmonic step field.
- the thickness of the selected path from the Width field.
Once the detection parameters defined, click:
- Detect to select the harmonic(s) depending on the user-defined parameters.
- Create RPM to use the fundamental frequency to calculate the rpm signal (to use as a RPM profile).
  If you needed, click Delete all points to undo the RPM selection points.
  The harmonics are detected.
  Tip: Now, you can isolate, listen and save the detected harmonics. You may apply additional modifications to the detected harmonics.