Whichtwostatementsaretrueaboutanalogtodigitalconversionofvoicesignalsforuseindigitaltelephonynetworks?()

A.Thethreerequiredstepsintheanalogtodigitalconversionaresampling，encoding，andcompression.

B.Thethreerequiredstepsintheanalogtodigitalconversionaresampling，quantization，andcompression.

C.Thethreerequiredstepsintheanalogtodigitalconversionaresampling，quantization，andencoding.

D.Theoutputofthesamplingprocessisapulsecodemodulation（PCM）signal.

E.Theoutputofthesamplingprocessisapulseamplitudemodulation（PAM）signal.