Forums › General Discussions › BB60c + TG44 – strange jumps on plot in SNA mode
- This topic has 3 replies, 2 voices, and was last updated 9 years, 5 months ago by
Ivan Ionov.
- AuthorPosts
Ivan IonovParticipant- This topic was modified 9 years, 5 months ago by
Ivan Ionov.
Hello,
I’m connecting my BB60c and TG44 with straight sma-sma connector.
On some settings I see a strange jumps up and down on SNA plot, on other settings plot is clear. See pictures.
Slight modifications of frequency start, stop or samples count can remove jumps or make them appear again.
first example –
Start = 1M, Stop=4.5G, sweep size = 500pts – everything works as expected
Start = 10M, Stop=4.5G, sweep size = 500pts – many jumps 3dB up and down appear on plotCan this be fixed?
Attachments:
You must be logged in to view attached files.
Ivan IonovParticipantSecond example –
Start = 1.1G, Stop=2G, sweep size = 500pts – ok
Start = 1.0G, Stop=2G, sweep size = 500pts – jumps appear on plotAttachments:
You must be logged in to view attached files.
AndrewModeratorHi Ivan,
The ‘jumps’ you are seeing are due to different calibration settings being applied to the individual IF paths. Each IF is 20MHz wide and each IF has its own set of corrections. For the TG sweeps we did not optimize the bands for overall flatness, as once you store thru the correction differences are stored in the offset and the trace should be flat. Your measurements will not be affected as long as the store through has been performed.
Regards,
A.J.
Ivan IonovParticipantI’ve rechecked this. It looks there’s something different.
Compare the same span with different num of points.
100pts – I see 3 dips on trace, every dip is 20MHz wide.
200pts – dips on trace have more details.
400pts – dips disappears!When I used a combination of SA44 + TG44, I did’t see this strange behavior.
Attachments:
You must be logged in to view attached files.- This topic was modified 9 years, 5 months ago by
- AuthorPosts
You must be logged in to reply to this topic.