input sensitivity

When i read about input sensitivity in Section2.4 of RF microelctronics(RAZAVI),
i am confused about input sensitivity caculation.

If a SNR of 8dB in a bandwidth of 200kHz is required, and the total NF is 4dB, so how to caculate the input sensitivity is about -109dBm?

-174dBm+10*lg200000+8+4

noise floor, band width, SNR, NF

hi, yubingz
the result of the eqution that you give is -147dBm, not -109dBm.
This question is in th e first page of chapter6 in RF electronics(Razavi).
what's the problem?

thx!

See below:

calculate it carefully