# Time Interference: Beats?

1. Feb 28, 2013

### InvalidID

So my textbook says that the equation for the frequency of beats is $|{ f }_{ 1 }-{ f }_{ 2 }|$ and the equation for effective frequncy is $\frac { { f }_{ 1 }+{ f }_{ 2 } }{ 2 }$, but what is frequncy of beats and effective frequency anyways?

Edit: Opps. Should've posted it here: https://www.physicsforums.com/forumdisplay.php?f=61

2. Feb 28, 2013

### ehild

See:
http://hyperphysics.phy-astr.gsu.edu/%E2%80%8Chbase/audio/sumdif.html#c1 [Broken]

ehild

Last edited by a moderator: May 6, 2017
3. Mar 1, 2013

### InvalidID

Thanks for the that! But what is effective frequency? The superimposed wave looks weird like this: http://hyperphysics.phy-astr.gsu.edu/%E2%80%8Chbase/sound/imgsou/beat4.gif [Broken]

So is the effective frequency the frequency of the wave in the dotted line or the solid line?

Last edited by a moderator: May 6, 2017
4. Mar 1, 2013

### ehild

The solid line.

ehild