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Post subject: Gain Compression with behavioral simulations
Posted: Wed Apr 14, 2010 1:25 pm
Joined: Tue Apr 13, 2010 4:00 pm
I have a "problem" concerning gain compression in top-level testbench considering overall system.
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 impedance.
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.