Why is a digital signal higher quality than an analog signal?

Answer 1

Digital signals allow error-correction to be encoded into the signal thus ensuring high-quality transmissions over a much greater distance than would be possible with analog transmissions.

Digital signals have a much higher rate of transmission, with fibre optic providing the optimum transmission rate.

Digital signals use less bandwidth, thus allowing a greater number of independent transmission channels over a given band of frequencies with no cross-talk between channels.

Digital signals can interleave audio, video and data in the same signal. This is what makes it possible to access the internet through your telephone line and make voice calls at the same time.

Digital signals are easier to encrypt.

Answer 2

1...because interference is essentially analog.

2...Digital signals are sent in packets of something like 128 bytes, and they contain integrity check devices like parity bits, checksums, hashcodes. If any of these fail, the receiver rejects the packet and requests a resend.

Satellite up and down links use variable power transmitters, and they back off the Tx power until a specific bit error rate (BER) is achieved in order to keep the amount of radiation sloshing around to a minimum.

Answer 3

It is not, but digital signal is less prone to distortion, as it has only a limited set of possible values (often it two).