in which condition P1db is prefered to iip3 and vice versa

I am asked about this question in my job interview,

I replied with: iip3 is prefered to p1db in some cases where the spectrum of the amplified signal is complicated such as many signal channels to more accurately predict the intermodulation of different channel signals

p1db is prefered especially in some amplification of some single tone signals to predict the am-pm effect of the amplifier

But I think what I replied is not what the manager wants , am I wrong? this is my first job interview?


and the second quesiton is why sigma-delta pll is better than integer-n pll,
I answerd with : 18+19 divisions is better than simple a 185 division by comparing some spur with 20db phase noise degration.
and still not what the manager wants I think.

i think that the idea is that IP3 is small signal value while P-1dB is large signal one

Re: in which condition P1db is prefered to iip3 and vice ver

thanks
but why iip3 is chosen ?(lna?) or why p1db is chosen ?(pa?)

Re: in which condition P1db is prefered to iip3 and vice ver

about the PLL better than what , other fractional architectures or better than integer N PLL

the answer will be different
khouly

to 3#
the question is revised, integer-n

Re: in which condition P1db is prefered to iip3 and vice ver

P1dB and IP3 are in most cases related, as a rule of thumb on LNAs IP3~P1dB+10.
so I didn't quite understood your question...
as far as I know, we usually take IP3 in receiver chain calculations to find out the dynamic range, the P1dB is used in transmitter to make sure you don't distort the signal or create IM.