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Below are all of the forum threads, including all
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Post subject: EVM Degradation at 54 Mbps OFDM
Posted: Wed Jan 20, 2010 9:03 am
Joined: Wed Aug 16, 2006
I designed a 802.11b/g Transceiver using Airoha's
AL7230 Chip-set. When I do EVM measurements on the
Transmitter antenna port using a Vector Signal Analyzer,
the EVM passes for all modulation Schemes and at all
output power level (17 dBm maximum) except 54 Mbps OFDM.
When I reduce the output power level by approximately 5dB
then the EVM test passes.
Is this problem due to
the Crest Factor of 54 Mbps OFDM signals. The Chip-set
data sheet satisfies the EVM requirements for a Power
output of 17 dBm. I have only placed a Balun and a switch
at the Chip-set Transmitter output pins. Can this degrade
my PA linearity