# Removing modulating signal from AM waveform in MATLAB

#### bosko47

Joined Mar 24, 2016
23
If I have my AM waveform (standard AM formula) and I multiple it by sinusoidal carrier of amplitude 1, will the result be a rectified AM waveform?

#### MrAl

Joined Jun 17, 2014
9,549
Hi,

Where did you get this idea from? We'd have to look into that.

Did you try it yourself?
F1=3*sin(wc*t)
F2=sin(wm*t)
AM=F1*(1+F2)
then:
AM*sin(wc*t)=?

AM*sin(wc*t)=|sin(wm*t)|
Is that what you are suggesting?

#### bosko47

Joined Mar 24, 2016
23
I got it from comparing the plots. Yeah that is the code I'm using. Does this help in recovering the modulating waveform? To me it looks like a rectified AM waveform. But yeah, I could be wrong...

AM waveform:

After being multiplied:

#### MrAl

Joined Jun 17, 2014
9,549
Hello again,

Ok now you have to try to recover the actual sine wave that was used as the message signal. To do that you'll need some low pass filtering and some offset. How you do that you'll have to figure out, and it has to work with all message frequencies unless you plan to use only one frequency ever.
It might work so you might try it.