Build a spec an from lab equipment need help

[DrGonzo]

I'm trying to assemble a basic spectrum analyzer from equipment around my lab and need some help.   I remember when I started out in PMEL one of my supervisors had gathered a few generators, o'scope, mixer and what not to show me the basics but I can't really seem to recall what all went into it. 

Is there anyone that could help me out? I have access to a wide range of generators, scopes, mixers and filters.

This "build" will be used as a general training example for several technicians.

Thanks.

[Hawaii596]

I just did a google search on "how to build a spectrum analyzer" and came up with quite a few interesting thoughts.  One of them included use of a CB radio, etc.  Rather than my parroting the results, you might try that (if you haven't already) and see if any of them look promising.

[DrGonzo]

Maybe I have didn't comunicate this properly.

I'm looking to assemble a group of lab standards to replicate the functionality of a spectrum analyzer, not build a hobby/enthusiast spec an.

I have checked Google.  Unfortunately it comes up (mostly) with searches on actually building spec ans.  I was kinda hoping there would be an "old timer" with an equipment block diagram (like 2 8340's some mixers and what not).

I'll keep looking or just spend some after hours time on it and post whatever I come up with.

Thanks

[Bryan]

What strikes me as toughest is going to be displaying frequency domain, with your generators, mixers & scope you could mix things up & examine something like modulation on a higher frequency signal but displayiing it would still come down to the time domain on the scope.  May using X-Y mode & a sweep ramp for one axis, but I'm going over my head here.
On the other hand I recall working with frequency selective voltmeters (HP/3586C) years ago, to me they amounted to spectrum analyzer but with a meter instead of crt display.
Good luck in your quest.

[pmelgeek]

I remember going through all this at Kadena and maybe Hickam about a million years ago.  It was one of the last things we did in K-3/4 for upgrade training. The intent was to pull together all the things that were learned in the section up to that point...ie, scopes, signal generators, attenuators, detectors, filters, etc.  You can use the basic block diagram shown at this link to get started. You don't necessarily need everything in the diagram, but the more pieces you can scrounge together the better.



http://oscilloscope-tutorials.com/Spectrum_Spectrum_Analyzer_Fundamentals.aspx




At the bare minimum, you'll need



A detector

A O'scope with an X-Y mode for the display.

A mixer

A signal generator with a sweep output (an 8340B will work for the Local Oscillator/Reference Oscillator and Sweep Generator)

A bandpass or notch filter to use as in IF filter (bandwidth). 



The 8340B does the job, but it's better if you can find a signal generator that has an external sweep input that you can drive with a ramp from a function generator though (3325 or equivalent). That way you can show how the scan width and sweep time functions work.



Enjoy!