I'm testing some RF receiver front ends at work.... Part of the spec asks for a 'noise measurement ' at bottom middle and top of the tuning range(200-300MHz). I have a calibrated noise figure analyser that comprises a noise generator and meter. The source is connected to the RF input, and the IF output is connected to the Noise Analyser input. I set the Local Osc. to 200, 250 and 300 (+ the IF) and read off the noise figure which is typically -5db,-4db and -5db. Can someone enlighten me as to what aspect of the receiver is being measured ???? All other obviously important parameters have been tested- bandwidth, rejection, mixer signal levels etc.
12 years ago