I am a bit confused about this differential base-emitter resistance.

It has been said that raspberry pi doesn't have much influence on small signal input impedance when CE with emitter degeneration is used. Well, I doubt this claim.

Can someone please explain why or when should raspberry pi be neglected in small signal input resistance calculus for CE with emitter degeneration?

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/q6KOQ.jpg