General description
The ACORR analyzer displays the autocorrelation function. The x- axis is the time as milliseconds. The y –axis is the correlation. If the input signal is white noise the autocorrelation function is zero in theory. If the input signal contains a sine signal, the auto correlation function is a periodic function. Maximums are in the following position:
tn = n * (1 / f)
where
f is the frequency of sine
tn is the n:th maxima in time
n is the index 0,1,2, ...
There are two sliders on the right side of the ACORR window. The left slider is used to set the middle position of window. The right slider is used to set the dynamic range. The left mouse button is used for zooming.
Display Settings
The popup menu is activated, when the right mouse button is pressed on the top of signal view area. The popup menu contains the following menu items:
Stop / Start
The display can be started or stopped using this menu item.
Auto Scale
The window area is scaled automatically according to the signal
Zoom Out
The display area is scaled back to the original size. Use this selection when you want to scale "backwards"
Grid
If selected, the grid lines are drawn.
Average
If selected, the power spectrum function is averaged on time. Using this display mode it is easier to see which frequencies contains energy, but fast changes are not shown.
Maximum
If selected, the maximum values are maintained.
Update Interval
Opens an update interval dialog, which is used to set the signal view update rate.
Properties
Opens the auto correlation properties dialog. The length of autocorrelation can be selected with the horizontal scroll bar. The length of autocorrelation window is shown as milliseconds. The average IIR factor parameter is used as IIR gain factor in the averaging process. It is used only when averaging is on. The smaller gain factor means that new values have less gain compared to the old values.
Copy to Clipboard
Copies the window to the clipboard.
Help
Gives information about ACORR analyzer.