Re: How to draw a spectrum of Pulse Amplitude Modulated signal?

On May 7, 8:35 am, ivanat...@xxxxxxxxx wrote:
Hello all!

I have a school project to do about PAM (Pulse Amplitude Modulation),
but these stuff aren't explained at all in our school class. I tried
searching google about PAM spectrum, but I almost didn't find
anything. Even in Wikipedia there was almost nothing useful about PAM.
I'm given a triangle signal with period=T,amplitude=A and a pulse
(square) carrier signal at 1MHz.
I can write this signal in a mathematical way, but I don't know how to
find its spectrum.
I have 2 things to do:
1) Write down an algoritm to calculate the spectrum of the modulated
signal.
2) Draw the spectrum of the modulated signal up to 6MHz.

If you help me with 1) I'll be able to do 2)

Thanks!

Thanks for being honest that this is a school project.

To go from the time domain to the frequency domain, you will need to
do a Fourier transform. Hopefully your instructor has covered Fourier
transforms, Discrete Fourier Transforms, and Fast Fourier Transforms.

In the field of Fourier transformation, there are some useful theorems
for shifting and modulation. You should be able to use these to
accomplish what you need. There is even a theorem for the spectrum of
periodic signals.

I hope this points you in the right direction. Has your instructor
worked a similar problem during lecture? If so try to follow his
steps. But also look at what tools (theorems) he has given you. I
don't think he expects you to invent something new.

Clay








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