RFSG and RFSA losing dBm

[GhostCole]

Hey,

I'm using 2 MIMO's systems, one with 4 RFSA and the other with 4 RFSG. My question (or problem) is that by usig 2 or more channels simultaneously with DIFFERENT frequecies, I'm loosing some levels as shown on the doc joint, and want to know why .

Thanks  

[ASEAN]

Hi GhostCole,

From the last pictures on your document, your source signal has a frequency at 1 GHz @ -10dBm, try to measure at RFSA at 1GHz and not 2GHz, maybe the one you've measured is the harmonics.

Also, can you try at first using same frequency and power level for all. If this is ok then you can proceed with your different settings.

Also, please take note what frequency and power level you set for each VSG modules.

Thanks.

Regards,

James

[GhostCole]

Hi James , 

From the first pic of my document, they all had the same freq (1 GHz even if by mistake I wrote 2GHz) and everything is cool, the problem is when I change for example from 1GHz to 2GHz on the RFSG Master but keep 1GHz on the RFSG Slave 1, I have nothing on my RFSA slave 1 UNTIL -10dBm on the RFSG slave 1 , and the RFSA slave shows -60dBm ... 

Why should I have both of them at the same frequency to inhib this lost ? (same problem by using the four RFSG )

Ossan

[j_a_m_e_s]

Hi,

Since you are sharing the LO signal between modules, if the Master VSG is generating on a center frequency of 2GHz, LO freq will be around 2GHz also, which will be exported and pass to the Slaves VSG.

Take note about this parameter: RF = IF +/- LO

Can you try limiting your 2nd or other frequency within 100MHz away from the Master center frequency.

Check this 5673 Specifications detailing the available bandwidth details:

http://www.ni.com/pdf/manuals/374959e.pdf

Regards,

James

[GhostCole]

Thanks for your answer James ! Effectively, by making those test with just 100 to 500 Hz difference, the lost is not so big ! 

But they are all supposed to be totally autonomous right ? 

[ASEAN]

Hi GhostCole,

Yes, as long as you are operating within the bandwidth specification of the RFSG module.

Remember that since you are sharing LO, frequencies should be within the 100MHz range.

Regards,

James