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#1 2015-Jul-13 23:28:36

Alannala
Member
Registered: 2014-Jul-31
Posts: 10

Question about TxGainRF

In "wl_example_siso_ofdm_txrx",
I control the TxGainRF in " wl_interfaceCmd(nodes,'RF_ALL','tx_gains',3,TxGainRF);"

I expect the performance will be better when I use larger TXGainRF parameter.
But the result is not! Is there any problem??

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#2 2015-Jul-14 08:10:44

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Question about TxGainRF

At the higher Tx gains you are likely clipping somewhere in the Tx circuit. This could be in the Tx VGA or the PA. Clipping will degrade the quality of your Tx signal, reducing effective SNR at any receiver. In other words, increasing Tx EVM decreases the SNR observed at the receiver, even if the total Tx power is higher. The optimal range of Tx gains depends on your waveform. For waveforms with higher peak-to-average power ratios (like OFDM) you typically must reduce the maximum Tx gain to avoid clipping.

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