How does demodulation work?

>>7978151
Fourier transforms

fourier transform
and lots of complex numbers

What class do I take to learn fourier transforms?

>>7978191
ocw.mit.edu/courses/mathematics/18-03sc-differential-equations-fall-2011/

MIT ocw lists it as a unit in their clas on differential equations

>The laws of nature are expressed as differential equations. Scientists and engineers must know how to model the world in terms of differential equations, and how to solve those equations and interpret the solutions. This course focuses on the equations and techniques most useful in science and engineering.

So there's your answer, I'd check it out there

>>7978191
Applications are usually taught in EE signals courses

>>7978196
>ocw.mit.edu/courses/mathematics/18-03sc-differential-equations-fall-2011/
They teach Fourier series in 18.03, not Fourier transforms.
Fourier Transforms tend to be introduced in the following classes:
- PDEs
- A course dedicated to transformation methods
- Functional Analysis

>>7978171
>>7978196
>>7978197
>>7978199
cheers

>>7978151
Multiply modulated carrier by itself (square it), remove sum (low pass), recover difference. Or simply rectify the signal (diode).