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NFA (N8975A) calibration in S band with high loss cable

Question asked by rvv on Oct 10, 2013
Latest reply on Oct 17, 2013 by Dr_joel
Hi...I am using NFA N8975A to measure the Noise Figure of my DUT in S (3GHz to 3.5GHz) & C ( 5.5GHz to 6.5GHz ) band frequency. I am using RF cables to connect the DUT to NFA. Complete RF Path is showing loss of 16 dB in S band frequency & 23 dB loss in C band frequency. 

Before measuring the Noise Figure of DUT. I am shorting the RF cables at DUT side using adapter &  then trying to normalize the Noise figure values using the Calibrate option in Instrument. But After completing the Calibration, Instrument is not showing 0 Noise Figure values at all frequency range. It is showing some value of 5 or blanck. 

I think NFA is not able to calibrate the path because it is showing 16dB loss. Is there any way to calibrate the instrument in S & C band frequency range at this loss.  

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