Choosing between NI PXI 2596 and 2597

[krishk24]

Hello

I am in need of switching for RF application upto 20 GHz. PXI 2596 (Unterminated)  and 2597 (Terminated) seem to be good candidates. Both can go upto 26 GHz with relatively low VSWR and IL.

The open channel isolation is identical at 60 dB upto 18 GHz.- see page 2 in http://www.ni.com/pdf/products/us/pxi2596_2597_2598_2599.pdf

By channel isolation I am assuming it is isolation beween any of the 6 signal Channels. Is that correct ?

Why would then someone choose 2597 over 2596 if the specs are identical. What benefit does the termination provide ?

By terminating  the unused Channels, signal energy coupling is minimized between the active Channel  that is connected to common and the other unused Channels. Shouldn't that be captured in the Channel Isolation spec ?

I am confused why one would order the 2597 which is more expensive and occupies 1 slot more than 2596.

Please help me understand. thanks

[MCOTO]

Hello,

The main difference between the two models mentioned is that the PXI 2596 is a dual 6x1 (SP6T) multiplexer, that means two independent 6x1 switches. Meanwhile the PXI 2597, as you have mentioned, is a single 6x1 terminated switch.

The answer for more of your questions could be explained basically by two concepts: Isolation and Impedance mismatch. Impedance mismatch causes Signal Reflections and could cause permanent damage on some devices and unexpected measurements or power dissipations issues. Termination could allow you to avoid some of the issues mentioned before (mostly if you will be connecting different sources to the switch). You can read more about RF Switching considerations from the link below.

http://www.ni.com/white-paper/2892/en/

Let me know if you have additional questions.

Regards,

MCOTO