Answer:
a digital signal requires an amplifier, which introduces noise into signal
No, an analog signal is generated by sensors such as a microphone and has a shape that resembles what is transmitted so much so that a receiver can easily reproduce the stuff that is transmitted on the signal just by following its shape and having an action controlled by the signal, as in a speaker. If you amplify a microphone analog signal then it can come out louder from a speaker. Analog signals are very natural, so that they don't need to be changed in shape between the transmitter input and receiver output.
A digital signal is converted to binary numbers represented by something changing either by switching on and off for zeroes and ones, or by changing tones, or by changing the shape of the signal based on the binary numbers which in simple cases are just measurements of loudness or brightness of what would have been an analog signal if it was not measured by computer circuits ... and it will be an analog signal again after the receiver decodes the binary number code and generates an output just like the input which was measured at the transmitter.
In other words, digital signals are complicated number codes for simple analog signals. Most of the time, digital signals seem better than analog ones because of the clever math used to process them, and some ability to tolerate "noise" which is called "errors" in digital signals or "static" in analog signals.