Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: Harmonic measurements
Posted: Tue Oct 03, 2006 11:26 pm
Joined: Tue Apr 18, 2006 10:40 pm
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?
Posted: Wed Oct 04, 2006 12:05 pm
Joined: Thu Apr 13, 2006 9:53 am
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.