NI-RFSG 5671 low level output problem

[jacky Wang]

A problem in NI RFSG.. The problem is when the output level from RFSG is low, there’s some much noise. There's a method recommended by NI that the problem could be somewhat corrected by using a 30dB attenuator just ahead of the dummy antenna and increasing signal strength by 30dB from the RFSG to compensate. . However, according to my observation, there's still significant noise.

 I don't know whether somebody have the same problem with me and hope  NI could investigate this issue ASAP.

Thanks!

Jacky

[ThiCop]

Hello Jacky,

I'm currently trying to answer all previously unanswered posts on this forum category.

So please let me know if I can still do anything to help you.

[micnot]

Hi,

I just ran over this "discussion" when I was looking for informations about low level output problems. I hope I get help faster than my predecessor 2006 --> 2012

I am sending a FSK modulated signal with my NI-RFSG (PXI-5671) equipment and I found out that my other Signal Generator (Rohde&Schwarz SMIQ 03B) is better in lower levels.

How did I find out?

• I am measuring sensitivity on a RF-transceiver in a certain debug mode
• I am sending the signal 10times. As long as 9 from 10 frames are counted on transceiver, I am decreasing power by 1dB
• The NI-RFSG will stop at -99dBm sending power
• The R&S SMIQ will stop at -104dBm sending power
• The signals are identical, only the upconversion differs

Could it be that on very low power levels all the noise is amplyfied also? What can I do to increase the Noise to Signal gap?

Any suggestions would be highly appreciated...

Thanks in advance, Michael

[ThiCop]

Hello Michael,

Can you repost this question as a new post and post the link in this thread?

I think this might be the easiest way to get more replies

I will then also continue posting in that new thread.

PS: In my effort to clean up this list of forum posts I did alot of "outdated replies".