Quadrature amplitude modulation

Quadrature amplitude modulation (QAM) is like playing with blocks that come in different shapes and colors. Imagine you have a bunch of blocks that come in two different shapes: squares and circles. Squares can be red or blue and circles can be yellow or green.

Now, let's pretend you want to send a message to your friend. You decide that squares and circles can represent different letters or numbers. For example, a red square can mean the letter "A," a blue square can mean the letter "B," a yellow circle can mean "C," and a green circle can mean "D."

But how do we show more than one letter at a time? That's where the "quadrature" part of QAM comes in. Instead of just using one block to represent one letter, we use two blocks - one square and one circle - to represent two letters.

Now, the "amplitude modulation" part of QAM means that we can make the blocks bigger or smaller to send even more information. We can make the red square bigger to represent the letter "A" but we can also make it even bigger to represent "AA" or "AAA."

So, when we put it all together, QAM is a way to send messages using different shapes and colors (squares and circles) and changing the size of those shapes (amplitude modulation) to send even more information.