Transmit BPSK from a text file in LabView; enable 8-bit IQ mode

[zaputo]

Hello,

I have a BPSK sequence I'd like to transmit, and it is stored as a spreadsheet of -1's and 1's. Adapting one of the niUSRP example VI's, I made this folllowing code. 

Currently it does not work, because the while loop doesn't transmit the array of values outside the loop until it finishes running (which it never does). But I feel this is a sloppy implementation - surely I can just store the output array as a variable. My issue is: Can I feed the USRP a single array of a few hundred elements and have it repeat once it reaches the end?

In other words, with a short sequence (a 1D array of -1 and 1's)  to transmit, is there a way to loop my transmission so it keeps broadcasting? 

A somewhat unrelated question is: How do I make use of the USRP's ability to transmit IQ symbols as 8-bit integers as opposed to 16-bit integers, which is the default setting? I have looked everywhere in the manuals for this, but no luck! I'd really like to use the 40 MS/s IQ rate, but am limited to 20MS so long as I use the 16-bit symbol representation.

Thanks!

Andrew

[netsirk]

Hi Andrew,

You should be able to consolidate the code in those two loops to run within one loop to read and transmit data while avoiding the tunneling issues you were experiencing. For your reference, the niUSRP EX Tx Continuous Async example demonstrates how to continuously transmit using the USRP.

With regard to your second question, 8-bit mode can be set using the Configuration:Advanced:Sample Width property accessed through the niUSRP driver. Setting this correctly should enable you to use the 40 MS/s IQ rate. Feel free to refer to the help documentation on this property for further information.

Regards,