6. a) For a binary bit stream, m(t), and a carrier c(t)-cos(10"xt), write down the general form of the modulated signals: (on-off) BASK, QPSK (or 4-PSK), 8-QAM b) Identify the type of carrier modulation scheme for each of the following constellation diagrams: -7A -5A 34 +4 +34 +5A +7A 00011 10011 (a) 00000 Also, if the symbol interval is 0.5 msec, what are the bit rates for the above modulation schemes? c) i) Briefly explain what is ISI and how Nyquist pulses can be used to mitigate it. ii) Is the bandwidth of 4-PSK is lower or higher than 4-FSK? Please justify your answer briefly. iii) Between M-ary PAM and M-ary QAM, which one will require higher power to transmit? Please justify your answer briefly, iv) From the noise immunity point of view, which of the following carrier modulation techniques is better and why: 16-PSK or 16-QAM? Please justify your answer briefly.