AnsweredAssumed Answered

PNAX Noise Figure Negative values

Question asked by rok on Jan 17, 2014
Latest reply on Feb 3, 2014 by rok

I'm trying to measure the noise figure of a downconverter with ~70dB of gain @ input power of -70dBm using a 50GHz PNA-X and opt 28 standard receivers with firmware A.09.80.20. The source attenuation on Port 1 is 40dB and the receiver attenuation on Port 2 is 5dB. I am using noise bandwidth of 1.2MHz, Averages of 250, and power calibration of -55dBm. I cannot calibrate at a higher power because I get source unleveled errors. I am using the scalar Noise figure for converters calibration and measurement. The problem is that I am getting negative noise figure values for virtually the whole band! The gain though and the output power seems okay though. I am using 47 to 49.8GHz as my RF range and 10.5GHz (quadrupled) as my LO. If someone can advise what I should try in order to fix this, that would be greatly appreciated.