Xspect User Introduction X. Rodet 4 Janvier 1996


Analysis/Synthesis Team,
IRCAM 4 Janvier 96

6.1 Fundamental Frequency (F0) Analysis

Estimation of Fundamental Frequency (named F0) is performed on the FFT of a segment. The FFT is displayed in the view according to user's choice (linear, log or squared magnitude), the most likely F0 value is shown in a text window. A vertical grid, at integer multiples of F0 is superimposed on the spectrum in the view.

This vertical grid is in fact a particular selection (called a grid) that is initially de-activated. in order that the user, in the standard mouse mode does not modify it. It can be re-activated. For this purpose, you have to select the mouse-mode "Selection Mode" by clicking on the middle one of the 3 buttons at the bottom of a window, i.e. the one with the 'I' icon.
Then, in this mode, clicking exactly on one of the lines of the grid (hard, hard!) changes its activation state. In this mouse-mode ("Selection Mode"), when the grid is active, you can stretch it by using right mouse button and drag, and you can displace the grid by using middle mouse button and drag.
In this mouse-mode ("Selection Mode"), when the right mouse button is pressed, the closest harmonic number, its frequency and the corresponding fundamental frequency appear in the identifier box at the top of the view.

In the "Standard Mode" (obtained by clicking the left-most button), use CTRL middle mouse button and drag to displace the grid and right mouse button and drag to stretch the grid.