Hello Zulkarnain. Greetings from my side.
Well thanks for showing interest. I already got cleared about the query and by the guidance of some generous person the problem and confusion is over. We can easily use two modulation schemes in our design and it is for some purpose we are using it. The consequence of distortion on the waveform is secondary but anyway thanks for pulling up an important and worth mentioning point.
Regards
Atul Sharma