Modulator and Demodulator (conceptual question)?

[neotriz]

Just a quick conceptual question.

If you have a sinusoidal signal of 3kHz with an amplitude of A, and it's going through a modulator, and then going through a demodulator, must the output of the modulator resemble exactly to the original signal?

The reason why I am asking is because when I was doing this in my lab, the output of the modulator had the same frequency of the original signal, but 1/10 of the Amplitude.

I thought it would have A/4 instead.

Comments?

 

[Floid]

It all depends on your system.

A perfect modulator and demodulator would result in an output that exactly matched the original signal.

In reality the demodulator stage may be such that you get a demodulated signal has an attenuated amplitude. Ideally this attenuation would be known and linear so that you can amplify the signal back to its original state.

So I guess I would say I need more detail to really answer better than that. Why did you expect A/4 to begin with? What type of modulation were you performing?

 

[neotriz]

Never mind, I just calculated the gain for the modulator and demodulator.

The reason I thought it would be A/4 is because I remembered the professor gave us an ideal circuit diagram that had a specified gain value for both the modulator and demodulator.

Thank you for your input!