Why don't computers do not use analogue signals to transmit information??

Question

I know what analogue signals are... just don't know the answer to this question!!

Answer 1

They do. For example, MODEMS use analog signals, with digital-to-analog and analog-to-digital conversion at each end.

Answer 2

Actually, the signal that computers transmit (say over the Internet) are still analog. Everything is analog. It is just a voltage on a wire.

The key is how the signal is interpreted. If it was interpreted as an analog signal, then it would have a value encoded as voltage level. As the signal degraded over long lines and with noise added, the result would change.

When a signal is interpreted digitally, it can have a single value (1 or 0) for a wide range of voltage levels. This means that if we know the amount of signal degradation and noise level on the line, we can set the voltage levels so that the signal can be interpreted without any loss of information.

That is the key.