How to measure Image Rejection Ration of Mixer ?

[pankaj.patil]

Hello Sir

How to measure Image Rejection Ration of Mixer ? Can you give me experimental setup to measure Image Rejection Ration of MIXER ?

Thank You

 

[biff44]

You hook a spectrum analyzer to the IF output port, and drive the LO and RF inputs with a synthesizer.

You set up Frf to be the desired signal and look at the IF out power level in dBm.

You then set up Frf to be the image, but the same distance from the LO as the desired signal. You look at the IF out power level.

The difference in the 2 IF out power levels is your image rejection.

 

[tony_lth]

Sometimes using variable RF, somtimes using variable LO.

 

[pankaj.patil]

You hook a spectrum analyzer to the IF output port, and drive the LO and RF inputs with a synthesizer.

You set up Frf to be the desired signal and look at the IF out power level in dBm.

You then set up Frf to be the image, but the same distance from the LO as the desired signal. You look at the IF out power level.

The difference in the 2 IF out power levels is your image rejection.

Thank you biff44
At different Frf we get different Image Rejection, then which Image Rejection should consider?
And what is theoretical formula to calculate image rejection ration to compare it with practical result?


thank you