I'm confused. Using an E4407B spectrum analyzer, I'm sweeping from DC (9kHz?) to 8GHz. I've lowered the resolution bandwidth to 3kHz. 8GHz divided by 3kHz is 2,667,667. If I wish to resolve the DC-8GHz spectrum in 3kHz increments, don't I need 2,667,667 data points? The CSV file I exported from the spectrum analyzer contains only 401 data points. Does this mean I missed several of the spurious signals I'm looking for? What am I doing wrong here?
Thanks, Jeff
Thanks, Jeff
Application Note 150 is a good place to start for understanding spectrum analysers, and good questions like this, and can be viewed here:
[http://literature.cdn.keysight.com/litweb/pdf/5952-0292.pdf?id=1000000159:epsg:apn]
In your case, see Chapter 2, the discussions on Resolving Signals, and Displays.
Basically, your reasoning is sound, but the display used in the ESA-Series only has a resolution of 401 pixels horizontally, not 2.6 million.
Due to design practicalities, there is a trade-off in terms of resolution, and sweep time, i.e. finer resolution means longer sweep times.
In practice these issues are often overcome by chopping the total frequency range of interest into smaller chunks, then sweeping across these smaller ranges with a narrow resolutuion bandwidth. Results can be logged to a file or computer for later analysis.
I hope this helps. Regards Simon Coleby.
Edited by: simon_coleby on Oct 13, 2015 11:16 AM