## M-ary QAM vs M-ary PSK |
Example 6.2 Example 6.3 | Question 6.6

#### Comparing the constellation diagrams of M-ary QAM with M-ary PSK we can see that the spacing between symbol states for QAM is greater than that for PSK which is restricted to having symbol states of equal amplitude and thus on a circle equidistant from the origin. The constellation diagrams shown here have been drawn to scale for equal average symbol power for both QAM and PSK systems, and the larger spacing between symbols for QAM means that the detection process should be less susceptible to noise. The peak power for QAM under these conditions is, however, greater than that for M-ary PSK and this must be taken into account if the transmission process is peak power limited. |

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