RFSA without using PXI-5660, or 5661

[Shazlan]

Hi,

I am planning to get a PXI system, which I'll use to test and verify RF signals from various radios. Most of the frequency of those radios are in the MHz range, and few of them are in the GHz. The PXI system I have in mind consist of a PXI controller (obviously), a 2.5 GHz 4x1 multiplexer (PXI 2594) and 2.7 GHz RFSA (PXI 5660 or 5661). On the software side, I'll be using LabVIEW and the toolkits under the RF and Comm Softwares. However, due to budget constraint, I may need to drop the RFSA for the time being.

Now, my questions/concerns:

1. If I were to get to PXI + multiplexer alone, will I still be able to analyze and test the radio signals, both in the MHz and GHz range? Let's assume that my team has sufficient theoretical knowledge to write LabVIEW codes to do the analysis. If the answer is yes, what difference does it make to have an RFSA?

2. I was told that, though I have an RFSA, the signals I will be getting are still raw. I still need to, 'somehow', pass them through the analyzer in the RFSA module for the signals to be analyzed. I ran through the forum and found out there are VI's, which are used to "instruct the signals to flow through the HW analyzer of the RFSA". Can someone please clarify this? Though this may be very basic, but I think I want to understand how the system works first before I commit financially 🙂

3. Refering to #2, assuming what I was told is true, what are the benefits of analyzing the signals using the HW, compared to using the software (refer to #1)?

Thanks!!

[mbb25]

If you don't get the 5660 or 5661, how do you plan to digitize the signals you want to analyze?  As for your question on the VIs that "instruct the signals to flow through the HW analyzer of the RFSA", the VIs being referred to are most likely configuration VIs.  The 5660 and 5661 have onboard DDCs (digital downconverters).  Although the 5660 can digitize a 20 MHz bandwidth signal, its DDC supports a max bandwidth of 1.25 MHz.  So for higher bandwidths the DDC is bypassed and the digitized IF signal is downconverted to IQ by the software.  It sounds like the above sentence is referring to configuring the 5660 to use the DDC.

The 5661 DDC supports the full 20 MHz bandwidth.  This reduces the amount of data that needs to be sent to and processed by the software.