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FAQ: Channel Correction FAQs for X-Series EXG and MXG

Question asked by tabbott Employee on Dec 18, 2012
*X-Series EXG and MXG FAQs*

1.     Q:  What is the difference between the User channel correction and the factory channel correction?
                A:  See EXG and MXG data sheet.

2.     Q:  For User channel correction, how many unique calibration files are supported?
     A:  We can support thousands on internal solid state drive.  They are small files 

3.     Q:  For User channel correction cal is it better to do a spot user cal or over an overlapping range? 
     A:  Overlapping is good idea but not required. Just specify the carriers you will run at is adequate.  The cal always runs ~+/- 90 MHz about your center frequency.  We over tune beyond +/- 80 MHz to ensure a flat frequency across the full 160 MHz. 

4.     Q:  For User channel correction cal when frequency is tuned out of “user” correction frequency range, is factory correction applied? 
     A:  Yes, we apply smoothing between cal arrays to ensure no discontinuity.

5.     Q:  How does DC cal effect channel corrections? 
     A:  If a DC cal is run with channel corrections applied this may or may not degrade performance slightly because you have changed the channel response of the system. 

6.     Q:  Do User channel corrections cover multiple attenuator steps? 
     A:  Yes. Bypass step, 0 dB step, & 5 dB step. These steps have the most VSWR change. Other steps have stable VSWR. 

7.     Q:  How long is the factory channel correction cal good for? 
     A:  The life of the source. Replacement parts come pre-calibrated, but user has the option of re-running the cal as a system. Also Agilent calibration software automatically runs this calibration by default, however it is not required to meet any performance specifications.

8.     Q:  Can you use EXA to run enhanced factory calibration or does it only work with PXA, MXA and PSA
      A:  No.  The EXA has not been qualified.

9.     Q:  When you perform the User channel correction routine do you need to compensate for cable between spectrum analyzer or power meter and source
     A:  No. We calibrated cable error by using MXG/EXG in CW mode to cal out absolute error.

10.     Q:  Can running user correction calibration over narrower range improve calibration? 
     A:  No. The number of point is always fixed a 5 MHz spacing.

11.     Q:  Do temperature changes effect the factory channel correction calibration?
     A:  No. However the IQ modulator should be re-calibrated when operating temperatures change.

12.     Q:  How do you know if you have the enhance factory channel calibration?
     A:  You must look under the service menu under IQ channel corrections.  See X-Series service manual for details.