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

[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

[Philosophe]

krishk24,

With regards to your questions, I am going to overkill this a little bit.

Here are the product pages for the PXI 2596 and 2597 respectively:

http://sine.ni.com/nips/cds/view/p/lang/en/nid/202258

http://sine.ni.com/nips/cds/view/p/lang/en/nid/202259

Here are the specification documents for the devices specifically:

http://www.ni.com/pdf/manuals/374243d.pdf

http://www.ni.com/pdf/manuals/374209d.pdf

Specifications in some areas of the two cards are a little different based additional hardware added for the termination feature.

In terms of your termination question, this document helps support this, as well as other switching considerations. Termination helps ensure the clean sending, and prevention of reflection, of a signal.

http://digital.ni.com/public.nsf/allkb/DEDE63FD1E29C740862579D1006A5E42

With regards to the comparison of the products, it really depends on the application one is trying to build. Termination may be a key component for some applications. Linked below is a good document with regards to RF switching and considerations on RF Hardware selection.

http://www.ni.com/white-paper/5769/en/

In terms of pricing, unfortunately I cannot provide an answer for this question.

The additional slot is in terms of the physical hardware itself and components just taking more space.

[krishk24]

I am aware of termination, characteristic impedance etc.

Why is the isolation spec identical between 2596 (unterminated) and 2597 (terminated) - and if the isolation spec is identical what benefit does 2597 provide over 2596 ?

[Philosophe]

Take a look at the reply on this forum post. This sums things up nicely. 

http://forums.ni.com/t5/RF-Measurement-Devices/Choosing-between-NI-PXI-2596-and-2597/m-p/2894564/hig...