Amplitude & Phase Modulation

Question 1

What is mQAM?

Answer 1

multiple Quadrature Amplitude Modulation is a modulation scheme that utilises both amplitude and phase modulation to transmit information. ie Each phase and amplitude represents a bit.

Question 2

What is the mQAM state diagram called?

Question 3

How many states are in 16-QAM

Answer 3

It has 16 states and each state represents 4 bits.

in general n-qam has n states and represents n^½ bits

Question 4

What bit ADC is needed for 64 QAM

Answer 4

3 bit ADC for I and Q signals

in general for n QAM, bits = log₂(n)

Question 5

What does phase error do to mQAM

Answer 5

Rotates the constellation diagram

Question 6

As the number of states increases in mQAM

Answer 6

The likelihood of noise and interference corrupting a symbol into an adjacent value increases.