How to measure the conversion gain of a Gilbert mixer?

[E-goe]

Gilbert Mixer

Yo

How can I measure( simulate: via transient and harmonic balance analysis ) the conversion gain of a Gilbert mixer?

Can you do it in the following way: You set the input of the RF and Lo amplitude to a certain value and you sweep the frequency of of the RF-source? Or is there another way of doing this?

Greetz E-goe

 

[rfsystem]

Re: Gilbert Mixer

That is the way used before Harmonic Balance or Periodic Steady State analysis:

Put a LO level to the mixer. RF signal is zero. Store the transient current of the Gilbert Cell devices (Bipolar or MOS). Measure the transient difference of the collector or drain current of two devices. Make an FFT. Measure the harmonic at LO. Then you have the conversion of the bias current into the Gilbert Cell to the LO frequency. That includes the LO coupling over base/collector or gate/drain cap to the IF port. To get the real conversion these coupling have to removed by complex substraction. That is done easy by an equation before FFT.