I have an N9030A with f/ware A.07.04
I am trying to make some IM measurements, so the input signal to the spectrum analyzer are two tones separated by 1 MHz with a centre frequency of 1 GHz (vary centre frequency 1- 6 GHz in 1 GHz steps).
The signal generation 10 MHz is used as the reference to the N9030A (i.e. the source and receivers are locked together)
I have my front end attenuator set to 20 dB. Given that my IM products are low down, I have the RBW=1 Hz and the span set to ~5 kHz. Under this configuration the SA is using the FFT sweep mode. I am using a Pk detector. There are 1001 pts in the frequency sweep.
Now, with the span set to 5 kHz, my IM level measures -98 dBm. If I change the span (LEAVING ALL OTHER SETTINGS ALONE), the measured IM level now measures -108 dBm. I left the sweep time autocoupled, so the sweep time changes slightly between the two span settings.
I would have thought that the amplitude of my IM tone would be independent of the span.
There is no mention in the A.07.06 firmware release of this being a known bug or that it has been fixed.
Can someone explain to me why when I change the span my tone changes by 10 dB? Is this a bug, is it a measurement limitation or do I have some conflicting settings that is causing this?
Thank you,
Andy
I am trying to make some IM measurements, so the input signal to the spectrum analyzer are two tones separated by 1 MHz with a centre frequency of 1 GHz (vary centre frequency 1- 6 GHz in 1 GHz steps).
The signal generation 10 MHz is used as the reference to the N9030A (i.e. the source and receivers are locked together)
I have my front end attenuator set to 20 dB. Given that my IM products are low down, I have the RBW=1 Hz and the span set to ~5 kHz. Under this configuration the SA is using the FFT sweep mode. I am using a Pk detector. There are 1001 pts in the frequency sweep.
Now, with the span set to 5 kHz, my IM level measures -98 dBm. If I change the span (LEAVING ALL OTHER SETTINGS ALONE), the measured IM level now measures -108 dBm. I left the sweep time autocoupled, so the sweep time changes slightly between the two span settings.
I would have thought that the amplitude of my IM tone would be independent of the span.
There is no mention in the A.07.06 firmware release of this being a known bug or that it has been fixed.
Can someone explain to me why when I change the span my tone changes by 10 dB? Is this a bug, is it a measurement limitation or do I have some conflicting settings that is causing this?
Thank you,
Andy
Span=5 kHz I measure -98 dBm
Span=2 kHz I measure -108 dBm
Thanks
Andy