52  N9912A FieldFox User’s Guide  
Increase Dynamic Range 
Dynamic range is the difference between maximum input power to the FieldFox 
receiver (without compressing the receiver), and the minimum measurable 
power (noise floor). Measurement accuracy is increased when the DUT response 
is at least 10 dB above the noise floor. For a measurement to be valid, input 
signals must be within these boundaries.  
A common application that requires a wide dynamic range is measuring the 
rejection band of a base station filter. 
   
The following steps MAY help you increase the dynamic range of your NA Mode 
measurement. The results you see will depend on the performance of your DUT. 
1.  Set Start and Stop frequency. 
2.  Press Meas 4  then Output Power High 
3.  Lower the IFBW. Press BW 2  then IF BW then 300 Hz 
4.  Increase Averaging. Press BW 2  then Average then enter 10. 
5.  Select S21. 
6.  Perform a Normalization Cal. Learn how page 64.  
7.  With RF OUT (port-2) open, press  Trace   6  then Data->Mem 
8.  Connect the DUT. 
The following image shows S21 measurements of a high-dynamic range filter 
using the above procedure. 
 
Blue trace – measurement WITHOUT step 7. 
Black trace – measurement WITH step 7.