NI 5781 Carrier frequency and I/Q rate settings

[josephkirmani]

I need to know how can I control Carrier Frequency and 1/Q rate settings in NI 5781 adapter module having NI PXIe-7962R. Like for e.g. in USRP we can do this using niUSRP Configure Signal built-in VI. I am asking this because I need to implement USRP code on NI 5781. 

Many thanks in advance.

[j_bou]

Hello josephkirmani,

The 5781 is a baseband transceiver and as such, will not allow you to modify the carrier frequency settings. The 5781 does not have an onboard signal mixer (and local oscillator) which is required for this type of signal manipulation. Controlling the carrier frequency and I/Q rate settings using a PXIe-7962R will require a different adapter module. The NI 5791 RF Transceiver Adapter Module should provide you with the functionality you are looking for.

NI 5791 - RF Transceiver Adapter Module for NI FlexRIO:
http://sine.ni.com/nips/cds/view/p/lang/en/nid/211063

I would also like to note that implementing USRP code onto to FlexRIO platform may not be a trivial process. On the USRP, all functionality is configured on a host side VI at a relatively high level. On FlexRIO, you will have to create a Host side and FPGA side VI. The FPGA code will be pretty low level. The LabVIEW shipping example project for the 5791R will provide you with a good starting point though (very simular to USRP RIO).

Regards,

j_bou

[josephkirmani]

Many thanks for your guidance. 

But I have one more question. In the getting started project of NI-5781, the frequency and amplitude of the signal is controlled using Basic Function generator VI.

So, similarly If I need to control frequency ond/or amplitude of my signal. How can I do that in NI-5781? Is there any built-in VI for it? I need to implement different types of modulation schemes and I have to control Frequency and Amplitude of my signal in those schemes.

Once again many thanks.

[j_bou]

Hello josephkirmani,

The Basic Function Generator VI is a function that can be run only on the host. In the example project you are referring to, this VI is used to generate a sample signal that will be sent to the FPGA and outputted through the adapter module. You will not find such a function available for use on FPGA. However, the “FPGA Math & Analysis” functions palette contains some functions that you might find useful.

What is the overall goal of your application? Are you looking to output a signal with the option to modulate the signal (frequency and amplitude) during program execution? 

Best Regards, 

j_bou

[josephkirmani]

Many thanks for your reply. Sorry for late replying. The answer to your above mentioned question is Yes I am looking to output a signal with the option to modulate the signal (frequency and amplitude) during program execution.

I have one more question: Is it possible to use "FPGA Math and Analysis" function palette on Host vi. Why Control Palette and Function Palette of FPGA vi is different from Host vi?

Once again many thanks. 

[Jacobson-ni]

Joseph,

Most of the math and analysis functions that you see on the FPGA palette have equivalent functions in LabVIEW which I would suggest using. You should be able to open most of the FPGA functions and copy the internals to use in your host application and it will probably work but not very well compared to the host's functions. The FPGA is almost always going to take inputs point by point, which is very good for the FPGA but not ideal for a PC which can more easily handle arrays of data.