what is the value of Vcm in this circuit?

[matin-kh]

Hi every one,
in this circuit M5 and M6 must work as differential amplifier and we have: gm5=gm6
but I don't know how should I initialize vcm, what is the value of it??
with best regards
matin

 

[D.A.(Tony)Stewart]

Adapting the gain of the RF and analog signal paths in order to absorb most of the input signal amplitude variation remains the most effective solution for optimizing the dynamic range of integrated receiver.

This article may shed some light.

 

[matin-kh]

thank you so much, but I have problem yet :thinker: I don't know I should connect Vcm to another part of circuit like a feedback or I should initialize it with a specific value.
thanks

 

[D.A.(Tony)Stewart]

It looks like a low impedance output