Hi,

I'd like to measure the Power Gain of the following PA.
Am I doing it correctly in the following way?
Please notice that I measure vin AFTER RS (not Before RS).

Pin_avg = avg (iin * vin)
Pout_avg = avg (iout * vout)

Gain = 10*log(Pout_avg / Pin_avg)

Should I measure vin before RS? (i.e. measure the voltage source's voltage).

Thanks!

 

Yes, it looks like you are doing it correctly.

No, you do not want to measure V_in prior to R_S because the power gain is the ratio of the power delivered by the amplifier to the power consumed by it. The power being dumped in R_S by the source is being consumed by the source, not the amplifier. Besides, it is possibly a modelled output resistance and does not reflect any true power consumed at all - the true power consumed by the amplifier could be a lot different, either higher or lower. The point being, that your amplifier doesn't care about those details, because it only sees the voltage applied to its input.

 

Hi
I thank you very much my friend!