AnsweredAssumed Answered

Spectrum Analyzer L.O. Issue

Question asked by SOLT_guy on Jul 14, 2012
Latest reply on Jul 23, 2012 by tabbott
Dear Sir:

      I own a spectrum analyzer and I use a HP 8593E spectrum analyzer (SA)  where I work.  

     Both units that I use have the same issue.    The SA local oscillator appears on the screen and sometimes it is difficult to make measurements with the LO signal so close to my test signal in frequency.   

     I am seeking to purchase another Agilent SA in the future and I want to know when did HP/Agilent begin making SAs that supress the L.O. signal from the display?  I am assuming that this problem has been eliminated over the years Agilent has been making SAs.

     My next question is an immediate question which I need to have answered:

      The HP 8593E SA has a bandwidth (BW) of 9KHz to 22GHz.   This is my problem.   I needed to measure a signal at approximately 10 KHz.  I input a signal out of my function generator and output the signal to the SA and I saw a blank screen on the display.   I was saying to myself, "where is my signal."

      I read the manual about measuring low frequency signals, or signals that are close in frequency to the LO signal, and the manual instructed me to use a "coupler" in my test set up.   The manual does not specifically assert which type of "coupler" to use.   There are lots of devices that use the term, "coupler", in the electrical industry.  

      Please tell me exactly how to correctly measure a low frequency signal using the HP 8593E SA. In your reply,  please specify the parts to use in the test set up , as well as, the test set up.   Measurement mode, or button presses, for low frequency measurements would be appreciated.

      It may be possible that my unit is not working correctly.  If you suspect this, please tell me how to test to see if it is not operating correctly.  

This is what leads me to believe that there may be a problem:

      The LO signal came up when I began to play with the frequency and span buttons.   I noticed a large LO signal at various settings and I know that this is nuisance signal.    

      If this is possible, please tell me how I can eliminate this signal and its harmonics from my measurements (or, at least, detect the harmonics, so that I know I am looking at a false reading).   

       Thank you for your time.

Edited by: SOLT_guy on Jul 14, 2012 7:49 AM

Edited by: SOLT_guy on Jul 15, 2012 12:44 PM

Edited by: SOLT_guy on Aug 2, 2012 9:36 AM