# Difference between revisions of "Amplitude modulation"

## What is AM?

Amplitude Modulation is the done by modulating the Amplitude of an sinoid Carrier signal using the incoming signal.

The Carrier signal is sinusoid with a fixed Frequency, usually much higher than the highest frequency occuring in the spectrum of the modulating signal. Amplitude Modulation schemes have been widely used in Analog Radio.

## Mathematical Setting

The output signal is the simple product of incoming signal and Carrier Signal with frequency f:

output(t) = input(t) * sin(f * t)

TODO: it would be nice to type formulas in TeX, is this working in this wiki?

Sure. But some prerequisites has to be met. Perhaps ist easier to use pictures of the formula (the manual way of what the wiki does).

## An Example

 Carrier Signal in time domain File:AM picture4.jpg Carrier Signal in frequency domain (to be added) Modulating Signal in time domain File:AM picture5.jpg Modulating Signal in frequency domain (to be added) AM Signal File:AM picture6.jpg AM Signal in frequency domain (to be added)

## Aquired Bandwidth

it would be nice to have a picture showing how AM signals in the frequency spectrum behave and how much bandwidth they allocate. A short overview of AM-related problems would be nice, too. Has anybody of you this info handy?