I am very new for receiver design. 

What is IF Flatness and RF levelling?

Are these achieved in signal processing or at RF level.

Thanks to one and all.

Regards

Gaurav Lohiya

IF Flatness usually refers to the flatness of the IF filter, which would indicate whether it is likely to introduce distortion or not.

RF levelling often means setting gains in the various stages of rf amplification to best manage SNR (noise figures) and dynamic range.   It might mean flatness, too, so that's the sort of thing that may be context dependent.   This one you'll probably want to ask whoever used the term to make sure you know what they meant.