Quadrature phase-shift keying

Okay kiddo, do you want to know about "quadrature phase-shift keying" or QPSK? It's a way to send information through the air without using any wires.

Imagine you have a flashlight and you want to send a message to your friend across the room. You can use the flashlight to blink in a pattern. For example, one blink could mean "hello" and two blinks could mean "goodbye." That's how we send information with QPSK, except instead of blinking a flashlight, we use radio waves.

QPSK uses two different things called "phases" and "amplitudes" to send information. Phases are like different colors of light - they can be different but they always look like light. Amplitudes are like how bright the light is - it can be turned up or down just like a light switch.

So with QPSK we have four different combinations of phases and amplitudes that we can use to send information. Each combination can represent a different letter, number or symbol. Just like your flashlight blinking pattern, we can use these combinations to send a message.

And when your friend gets the message, they can use their own QPSK system to decode it and read the message you sent! Pretty cool, huh?