Frequency Modulation (FM)

Macro: FMdlg

This button brings up the Frequency Modulation dialog, and is shown depressed when FM is activated for this stream. The actual FM toggle button is at the top of the pop-up dialog.

FM Overview

Frequency modulation is when the frequency of one signal (the 'carrier') is controlled (modulated) by the instantaneous value of another (the 'modulator'). Moving the slider on a child's slide whistle modulates the pitch (frequency); here we are effectively moving the slider automatically.

'Vibrato' in music is a form of frequency modulation, although in real-world instruments and voices there is often a certain amount of amplitude modulation ('tremolo') added by the vibrato mechanism. Vibrato typically involves a modulation rate of several Hertz.

Macro Notes:

If the Stream dialog is open, FMdlg=1 opens the FM dialog, FMdlg=0 closes it, and FMdlg=x toggles between open and closed.

Note that you do not need to open the FM dialog to change any of its controls directly via macro command.

See also Frequency Modulation Dialog, Waveform Stream Controls