I have a "problem" concerning
gain compression in top-level testbench considering
The TX budget is as below:
RF side -- external rf diplexer -- external
PA -- external RF filter -- rf amp -- 2nd mixer
-- external if filter -- 1st mixer -- if amp --
external if diplexer -- IF side
all RF blocks
has 50 ohms ref. impedance and IF blocks 75 ohms
I am using behavioral models in
verilog-a in each block. I am having compression
gain in 2nd mixer (specified in the model as 7 dB
and simulated 4.5 dB) and rfamp (specified 10 dB
and simulated 8.5 dB). Also, external PA had simulated
gain 2 dB more than specified.
I am trying
to understand why it is happening because apparently
blocks linearity is ok to avoid gain compression.
I thank if anyone has an idea about this.