In this video Keith Parsons from www.wlanpros.com shows how to visualize different modulation schemes used by 802.11
Chapters:
00:00 - Start
00:10 - Different Types of Modulation
00:22 - Binary Phase Shift Keying (BPSK)
03:22 - Quadrature Phase Shift Keying (QPSK)
05:35 - 16- QAM
06:58 - 64- QAM