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802.11 a/g power control - RF Cafe Forums

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 Post subject: 802.11 a/g power control
Posted: Thu Jun 23, 2005 10:48 am 

Joined: Thu Jun 23, 2005 10:47 am
Posts: 6
Hello all, does anyone know where I can find information on the power control scheme in 802.11a/g systems?

Is the transmit power controlled by adjusting the output of the 802.11 baseband processor, or is the power controlled in the RF portion of the circuit using a variable gain amplifier?

It sounds like 802.11h is the brains of the transmit power control system, but I would like to find out the physical implementation.

Thanks so much for any tips!

 Post subject:
Posted: Fri Jun 24, 2005 11:04 am 
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Joined: Sun Aug 03, 2003 2:02 pm
Posts: 653
Location: Erie, PA
Greetings wahooburger (sounds a lot like my nane ;)):

Power control is implemented in the transceiver. The transceiver output typically feeds directly into the PA. Most WLAN PAs now have a built-in power detector that feeds back to the transceiver. Bias control on the PAs is used to achieve best performance (EVM, harmonics, Psat, etc.), but the gain of the PA is usually fixed by design (about 30 dB for a 3-stage device).

SiGe, RFMD, Fairchild, Gatax, Tavanza, RFIC, RF Solutions, Skyworks, and many others make WLAN PAs. You can get scads of info from their websites.

- Kirt Blattenberger :smt024

Posted  11/12/2012