Given, frequency of message signal, fm=15‌kHz=15×103‌Hz Let fc be the carrier frequency, then upper side band frequency =fc+fm ⇒‌‌1515=fc+fm ⇒‌‌fc+fm=1515‌‌‌⋅⋅⋅⋅⋅⋅⋅(i) Similarly, lower side band frequency fc−fm=1485‌‌‌⋅⋅⋅⋅⋅⋅⋅(ii) Adding Eqs. (i) and (ii), we have 2fc=3000 ⇒fc=1500‌kHz=1.5×106‌Hz=1.6‌MHz