Still, hatsunearu is correct. The page is grossly wrong, absolutely no modern WiFi modulation technique uses 8-PSK. Have a look at http://mcsindex.com/ 11a/11n/11ac all use BPSK, QPSK, 16-QAM, 64-QAM, and (for 11ac only) 256-QAM.
I know. And not a word on forward-error correction, trellis codes, automatic gain control, beam steering or MU-MIMO. Is this for babies? They don't even touch on low-noise amplifiers. Much less DAC and ADC performance. Where's the link a primer on FFT?
