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= Transmitter Characterization =

The IEEE 802.11 Standard specifies minimum tolerances on the quality of emitted waveforms from WLAN devices. These tolerances are specified in as Error Vector Magnitude (EVM) in dBm. For the OFDM PHY in 802.11a/g, the tolerances are presented in Section 18.3.9.7.4 of 802.11-2012 and are reproduced below:

||=  Rate  =||=  Modulation / Coding  =||=  EVM (dBm)  =||
||  6 Mbps  ||  BPSK 1/2  ||  -5  ||
||  6 Mbps  ||  BPSK 3/4  ||  -8  ||
||  12 Mbps  ||  QPSK 1/2  ||  -10  ||
||  18 Mbps  ||  QPSK 3/4  ||  -13  ||
||  24 Mbps  ||  16-QAM 1/2  ||  -16  ||
||  36 Mbps  ||  16-QAM 3/4  ||  -19  ||
||  48 Mbps  ||  64-QAM 2/3  ||  -22  ||
||  54 Mbps  ||  64-QAM 1/2  ||  -25  ||


The 802.11 standard also specifies the procedure in which similar values can be measured for WLAN devices in Section 18.3.9.8 of 802.11-2012.