(b) (c) A phone system uses 4-ary signalling for communication purposes. The link has a flat frequency response up to 300MHz, with negligible group delay distortion within 100m range. For a baseband channel, the link can support symbol rate up to twice the available bandwidth. (i) (ii) What is the baseband information transfer rate that can be accommodated by the link? If the noise introduced by the link is improved to -40 dB with respect to the signal power, what is the resulting maximum information transfer rate? [Hint: C B log2(1 + S/N)] For the frequency range from 0Hz to 2(fs + fm), draw the spectrum of the PAM (Pulse Amplitude Modulation) signal with a sampling frequency fs and the highest message frequency fm.