For the ADMV4728 beamformer, I have seen two numbers for the noise figure. First NF is "eight channel active" which is 13 dB and second NF is "one channel active" which is 4 dB. In the footnote it has described that the difference between these two numbers is due to number of active channels. My question is that when it says active channel, is the active channel on Rx mode or Tx?
In addition, it seems that the beamformer has 16 active channels (to support 8 dual polarization antennas). So should we define "sixteen channel active" NF?
Finally, I would like to know which of these NF should be used in link budget calculations?