Description
I am using a FSW or FSV/A3000 spectrum analyzer together with the FS-ZXX harmonic mixer. I want to use the Auto ID function in order to suppress the unwanted mixing products.
Auto ID function for modulated signals to suppress unwanted mixing products
I am using a FM modulated signal and it looks like the Auto ID function is not working properly. I can still see mixing products in the spectrum.
Resolution
When performing the Auto ID function, the spectrum analyzer performs two sweeps with different LO settings at the LO port of the spectrum analyzer.
The Auto ID function uses this two measurments to recognize the unwanted mixing products and removes them from the spectrum and only diplays the signal of interest.
If anything changes between these two measurements the signal at the input port may not be stable.
That means that the unwanted mixing products can not be recognized/substracted by the Auto ID function.
So the Auto ID function should only be used for CW signals.
