How does voice over wire or over internet work? How can we hear and understand another person in real time over such a distance via a digital transmission?

Question

Honest question I cannot wrap my mind around. How the hell does this work?

In: Physics

Answer 1

Sound is a compression wave, like pushing and pulling air molecules. Those pushes and pulls of air create high and low pressure against a tiny diaphragm (Im sure you’ve seen a speaker 🔈). When that cone moves against a magnet, it creates a voltage.

Now imagine that voltage wave, which goes up and down like an ocean wave, is sampled – thousands of times per second you measure the height of the wave and record it as a digital number.

We’ve found creative ways to make that height measurement data smaller so there’s less to move, and therefore faster to send. But then that data is sent a lot like Morse code – push the button down, 1. Let up, 0. Millions (not a typo) of times per second.

The receiving end accepts all those wave height measurements and knows the time intervals they were taken, and reconstructs an analog voltage, which then is connected to a speaker coil and moves that coil back and forth to create air pressure waves in the air.