Help with drawing demodulation/modulation graphs?

[Lols123]

Hey guys, having trouble drawing the modulated signal when given the carrier and vice versa, i.e drawing the demodulated signal. Got any tips?

Heres an example:

[Bozo]

Basically, what you need is the GAIN of the amplifiers. They either gave you a gain value or there was a graph on the previous page with a linear region. Refer back to that graph and calculate the gradient of it which is the gain.   NOTE: the milli volts on the x axis.

Now once you have the gain, you can calculate the output voltage as so

Vout=GAIN *Vin
Vout=GAIN*100x10^-3 (The peak of the input wave as shown in the graph above).

Also to note, on the Vout vs Vin graph (The one with the linear gradient) is whether the gradient is positive of negative which will help you determine whether the amplifier is inverting or non-inverting.

+ve gradient = non inverting
-ve gradient = inverting which means the sinusoidal wave when drawn would flip.

[Lols123]

erm...not that....
modulation and demodulation :/
all the carrier wave stuff..

edit: sorry attached the wrong pic

[ttn]

I'd just copy the the top edge of the modulated signal?

to modulate, I would draw a dotted line of the signal, then underneath the reflection of that signal, and draw the modulated signal in between if that makes sense lol.

[Lols123]

would you be able to upload a picture or something to visually show me? :/
cause i dont really get what you said D:

[ttn]

The blue is showing the demodulation. So you basically just copy the shape of the top edge.

The red shows the modulation of the blue signal. As you can see you end up with the same wave as the original on the top.

[Lols123]

ahh i can see it now
just one more thing though
how do you know the amplitude of the curve
like the answer has it much longer than you do (2 boxes)

[ttn]

That, I'm not sure about. It didn't give any sort of scale so I don't know if it even matters.

[Shark 774]

ahh i can see it now
just one more thing though
how do you know the amplitude of the curve
like the answer has it much longer than you do (2 boxes)

It doesn't matter, unless they give you a scale. Which, according to my teacher, they won't because it's just too complicated.