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Measurements >> RF Measurements >> Voltage Conversion Gain Mixer
https://designers-guide.org/forum/YaBB.pl?num=1354003417

Message started by DDC on Nov 27^th, 2012, 12:03am

Title: Voltage Conversion Gain Mixer
Post by DDC on Nov 27^th, 2012, 12:03am

Hello,

I want to measure the voltage conversion gain of my gilbert cell downconversion mixer (frf = 2.4GHz, flo = 2.34GHz). I think I can only measure the power conversion gain with a spectrum analyzer. Is there an equation to calculate the vcg from s-parameters or an other method to evaluate this ? Thanks for response.

Title: Re: Voltage Conversion Gain Mixer
Post by rfidea on Nov 27^th, 2012, 11:35am

Use the relationship between voltage and power, P = Vp^2/(2R). So, is your source resistance is RS and the load resistance is RL the voltage gain is

Gv = Vout/Vin = sqrt(Pout*2*RL)/sqrt(Pin*2*RS) = sqrt(Gp)*sqrt(RL/RS)

or in decibel

Gv,dB = 20*log(Gv) = 10*log(Gp)*10log(RL/RS) = Gp,dB*10log(RL/RS)

Usually both your signal source and spectrum analyser is 50 ohm. Is your inputs and outputs designed for handling that?