Re: Turning up the power?

From: Jim Thompson (jim_at_musenki.com)
Date: 2002-01-01 08:49:35 UTC

Hmm,

http://www.intersil.com/rnwscripts/custfaq.cfg/php.exe/enduser/std_adp.php?p_sid=RcOJM64g&p_lva=001205-000852&p_refno=001228-000008&p_created=978021964&p_sp=cF9ncmlkc29ydD0mcF9yb3dfY250PTU3MyZwX3NlYXJjaF90ZXh0PSZwX3NlYXJjaF90eXBlPTMmcF9wcm9kX2x2bDE9NyZwX3Byb2RfbHZsMj1_YW55fiZwX2NhdF9sdmwxPX5hbnl_JnBfY2F0X2x2bDI9fmFueX4mcF9zb3J0X2J5PXByb2R1Y3RzLm5hbWUmcF9wYWdlPTEy&p_li=

says:

PRISM, Boost the output
  
Question
 

Currently our PC card has 16 dBm output power measured at SNA connector. Is there any method to boost the output to 20 dBm or more?   
Answer
 

Increasing the output power may be accomplished several ways, most involve higher cost. The P1dB of the HFA3925 is a minimum of 22.5dBm.

The DSSS waveform and IEEE802.11 side lobe spectral mask requires a linear response with minimal distortion. Typically the HFA3925 output is approximately 21dBm. This power level make maximum use of the Power Amps capability without excessive distortion.

Removing output filtering will increase output power, but cause the radio to fail FCC spectral requirements. A couple of ideas to increase Pout follow;

  1. Better/Lower loss output/preselect filter
  2. More gain in the transmit chain, prior to the PA. (This reduces distortion from earlier chain elements allowing the PA to be driven harder.)
  3. Buy a higher output PA - such as is available from Celeritek CCS2930 or CMM2320. Problems include, T/R switch distortion more supply current, more out-of-band spur power, space and cost.

which doesn't bode well for just setting a register.

Jim

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