So I've been looking around the internet for a good explanation/derivation of the expression e = (Ec+Ei*sin(wi*t)}*sin(wc*t)

Through this expression, it's very clear that the amplitude of the carrier wave is time-varying with the frequency of the intelligence wave.

But the question is how do we get here?

I've seen loads of derivations where they partially show how it's done, like:

e = A*sin(wc*t)

A = Ec+Ei*sin(wi*t)

---> e = (Ec+Ei*sin(wi*t))*sin(wc*t)

But this still assumes that e = A*sin(wc*t) is known.

I've read on the Swedish version of Wikipedia that "the nonlinear device" (which is not very well explained by nor the book or our teacher.) is supposed to be as quadratic as possible.

Any way... I simulated this circuit, and it produced the expected result, an amplitude modulated signal.

The signal going into the base of the transistor is the intelligence added to the carrier, Ec+Ei.

So what is happening in the "non-linear device" to go from

Ec*sin(wc*t) + Ei*sin(wi*t) ----non lienar---> e = (Ec+Ei*sin(wi*t)}*sin(wc*t)

I've also read about the upper and lower sideband has something to do with the result, and that these side frequencies come as a result of the non-linear device.

So if someone could provide a bit of insight into this matter would be great!

I realize that it's probably much more complicated than I can imagine.

Thank you!

Through this expression, it's very clear that the amplitude of the carrier wave is time-varying with the frequency of the intelligence wave.

But the question is how do we get here?

I've seen loads of derivations where they partially show how it's done, like:

e = A*sin(wc*t)

A = Ec+Ei*sin(wi*t)

---> e = (Ec+Ei*sin(wi*t))*sin(wc*t)

But this still assumes that e = A*sin(wc*t) is known.

I've read on the Swedish version of Wikipedia that "the nonlinear device" (which is not very well explained by nor the book or our teacher.) is supposed to be as quadratic as possible.

Any way... I simulated this circuit, and it produced the expected result, an amplitude modulated signal.

The signal going into the base of the transistor is the intelligence added to the carrier, Ec+Ei.

So what is happening in the "non-linear device" to go from

Ec*sin(wc*t) + Ei*sin(wi*t) ----non lienar---> e = (Ec+Ei*sin(wi*t)}*sin(wc*t)

I've also read about the upper and lower sideband has something to do with the result, and that these side frequencies come as a result of the non-linear device.

So if someone could provide a bit of insight into this matter would be great!

I realize that it's probably much more complicated than I can imagine.

Thank you!

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