Editing Orthogonality (section)

===Orthogonal frequency-division multiplexing===
{{Main|Orthogonal frequency-division multiplexing}}
Another scheme is [[orthogonal frequency-division multiplexing]] (OFDM), which refers to the use, by a single transmitter, of a set of frequency multiplexed signals with the exact minimum frequency spacing needed to make them orthogonal so that they do not interfere with each other.  Well known examples include ('''a''', '''g''', and '''n''') versions of [[802.11]] [[Wi-Fi]]; [[WiMAX]]; [[ITU-T]] [[G.hn]], [[DVB-T]], the terrestrial digital TV broadcast system used in most of the world outside North America; and DMT (Discrete Multi Tone), the standard form of [[ADSL]].

In OFDM, the [[subcarrier]] frequencies are chosen{{how|date=May 2019}} so that the subcarriers are orthogonal to each other, meaning that crosstalk between the subchannels is eliminated and intercarrier guard bands are not required. This greatly simplifies the design of both the transmitter and the receiver. In conventional FDM, a separate filter for each subchannel is required.