What are the characteristics of the constellation when the carriers are not synchronized?

What are the characteristics of the constellation when the carriers are not synchronized?

1.

White noise interference: the noise is random, and the falling point will be distributed around the ideal value like a cloud.

2.

Phase noise interference: Because the modulator is not good, the constellation rotates around the center, and the signal strength is the radius of the rotation diagram.

3.

Gain compression: due to signal compression distortion, a non-square constellation appears, and the larger the QAM peak value, the greater the distortion.