Hi,
     I got confused about one noise measurement in Commom source topology. It is a common source and load is a resistance Rd. Output noise is proportional to root(Rd) , it means it is proportional is some way. Therefore, if Rd increases, so as noise power. But if we consider inut referred noise , it is actually inversely proportional to Rd.
Can someone explain this ?

Best Regards
Abhishek

I understand the math part. I want the intuition behind it. Output noise power increases as Rd increases. But input referred noise power decreases. Why this paradox? I mean if we are to reduce the noise say thermal, then we should reduce the value of Rd. I am getting confused with this input referred noise. I understand physically there is no such thing, it is just a tool of understanding circuit noise, isn't it? But the real thing is output noise power. Please forgive my ignorance, I am learning.