Harmonic measurements - RF Cafe Forums

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jabb
 Post subject: Harmonic measurements
Posted: Tue Oct 03, 2006 11:26 pm 
 
Captain

Joined: Tue Apr 18, 2006 10:40 pm

Posts: 11

hi...i've this spectrum analyzer that goes up to 26.5 GHz. my DUT runs at 18 GHz; if I want to check the second (36 GHz) or third harmonic (54 GHz) can that be done using the spectrum analyzer or because since it goes up to 26.5 GHz, it won't sense the signal at those harmonics?

is the only other thing possible is to use mixer to down convert?
 
   
 
RFTEJerry
 Post subject:
Posted: Wed Oct 04, 2006 12:05 pm 
 
Captain
User avatar

Joined: Thu Apr 13, 2006 9:53 am

Posts: 17

Location: Florida

Hello jabb,

Your spectrum analyzer will not be able to measure your harmonics directly because they are out of the tuning range of the spec-ana. You will need to add an external down converter between your signal and the spec-ana. Many spec-anas can output their LO to external mixers to downconvert the signal to the range of the spec-ana and then compensate for the down conversion so you don't have to do the math.

I have down this with several HP (Agilent) spec-anas in my career. The reason the spec-anas LO is used to keep everything in "sync" with the internal sweep of the spec-ana.

Good luck,

RFTEjerry.

Posted  11/12/2012