# Thread: Function for graphing differences in Hertz?

1. ## Function for graphing differences in Hertz?

I have a function y=sin2pi*f*t. I am trying to find the number of beats when you add 2 different frequencies up. For example 440hz and 445hz. But when I graph this function there are way too many periods, it's unreadable. Is this function a good function to use to find the sum or beats of 2 different waves measured in Hz?

2. Originally Posted by bilbobaggins
I have a function y=sin2pi*f*t. I am trying to find the number of beats when you add 2 different frequencies up. For example 440hz and 445hz. But when I graph this function there are way too many periods, it's unreadable. Is this function a good function to use to find the sum or beats of 2 different waves measured in Hz?
The beat frquency is $\displaystyle |f_1 - f_2|$ which in your example is equal to 5 Hz. So the frequency of the 'envelope' is 5 Hz and therefore the period is 1/5 sec. The periods of your two since waves are 1/440 and 1/445 sec.

So care is needed in choosing the window on your calculator ......

It might be easier, for graphing purposes, to use two frequencies that are closer to each other. Perhaps 440 Hz and 441 Hz .......

3. Originally Posted by mr fantastic
The beat frquency is $\displaystyle |f_1 - f_2|$ which in your example is equal to 5 Hz. So the frequency of the 'envelope' is 5 Hz and therefore the period is 1/5 sec. The periods of your two since waves are 1/440 and 1/445 sec.

So care is needed in choosing the window on your calculator ......

It might be easier, for graphing purposes, to use two frequencies that are closer to each other. Perhaps 440 Hz and 441 Hz .......
When I try graphing these functions like sin(880pi*x) or sin(882pi*x) there are far too many beats to count. Or are beats a large group of waves that make a certain shape?

4. Originally Posted by bilbobaggins
When I try graphing these functions like sin(880pi*x) or sin(882pi*x) there are far too many beats to count. Or are beats a large group of waves that make a certain shape?