What is described by the constellation diagram of a QAM or QPSK signal?
How many carriers may be present at the same time
The possible phase and amplitude states for each symbol✓الإجابة الصحيحة
Frequency response of the signal stream
The number of bits used for error correction in the protocol
الشرح
A constellation diagram plots every allowed symbol as a point on in-phase and quadrature axes, so the distance of a point from the origin is that symbol's amplitude and its angle is that symbol's phase. The number of points shows how many states, and therefore how many bits, each symbol carries.