There are billions of mobile phones all communicating with each other sending wireless signals across the globe. How does each signal know where to go exactly, and how are they not intercepted by other signals?
In: 9
The signals go in all directions, and there are thousands of them zipping around all the time.
The genius way they don’t all get mixed up is by using resonant circuits. If you’ve ever tuned a guitar, you’ve probably seen that when a string is tuned exactly to the tone of another, the other will start vibrating as well. Radio tuning works the same way, making sure the receiver only vibrates along with the intended transmitter.
These circuits are incredibly selective, and can easily find the whisper of your particular phone within the roar of every other transmitter. It’s like going to a rock concert and only hearing when the keyboardist hits middle C.
As for interception, phones use frequency hopping, which means the sender and receiver change their tuning automatically several times a second, according to a pattern which an outside receiver won’t know how to follow. So even if you tuned into one of the frequencies and started listening, you wouldn’t get very much information.
This also help with transmission robustness. If you happen to be transmitting on someone else’s frequency, you’ll soon leave it because you both hop to different frequencies. There are built-in protocols for how they should react to interference in order to mostly keep it from affecting the call.
Latest Answers