help with NI 5640R card

[sandeep palreddy]

Hello,

I have a question regarding generating a sequence of waveforms. I want to use the example "NI 5640R analog input and output" (I know this example is capable of generating a QAM or single tone signal) and make changes such that the when i run the VI i want the output to be switching between single tone and QAM and i want this to happen until i stop the VI.

And in the future i want to add another waveform (sawtooth) and want my output to be switching between the 3 waveforms. Any help regarding this will be grately appreciated.

Thanks,

Sandeep.

[Mauricio Capistran-Garza]

Hi Sandeep,

Let me try to understand your use case a little bit better. Do you want to be able to switch between different waveforms? Or do you want the waveforms to automatically switch at their last sample? Also, do you want the waveforms to be phase continuous? in other words, do you want the NCO phase to start where it left off the previous waveform or you don't really care?

Basically, I'm trying to figure out if this needs to be hardware timed or it can be software timed. If you need it to be hardware timed, then you will need to write both waveveforms to the memory and then maybe add some logic to control the switching. The caveat here is there isn't a lot of memory, so you might not be able to store many waveforms. Another option is to overwrite the waveform with a new one every time you want to switch. This can be tricky if you can't tolerate glitches while you are switching the waveforms. One last opiton is to constantly stream data to the board. In this case you would be limited by the bandwidth at which you can stream the data.

- Mauricio

[sandeep palreddy]

Hi Mauricio,

                  I want the waveforms to automatically switch at their last sample and i dont care about waveforms being phase continuous. All i want is to the program to be able to switch between waveforms automatically. I want to do this using software (Programming ). Is there a way you can help me with this? If possible can you change the example "NI-5640R Analog Input and Output" to make the vi do this and give it to me? Any help regarding this will be grately appreciated.

Thanks,

Sandeep.

[IF-RIO]

hello sandeep

This is rajesh, i am currently working on labview and NI PCI 5640R; i have studied the datasheets of the 5640R board and i tried to edit the project for AM. yet i could make it using FPGA gates only... what makes host different from FPGA target, i mean in terms of logic... where to put the actual logic say for AM, either in HOST or the am.vi.... please help me in this context...as i am working for the past one month on labview... help me urgently.... because our project is on hold....

[IF-RIO]

Also sandeep please give me ur e-mail id: so that i can explain more clearly about my problem.... hope u reply soon... rajesh, rajeshg@icsglobal.biz

[JerryAL]

Hi Rajesh

I suggest that you read the “Getting Started with the “NI PCI-5640R IF Transceiver and the LabVIEW FPGA Module”.  I suggest trying the example as well as learning how to resave one of the shipping examples that you can use as a base to start your application.

In terms of the host, or the FPGA, the main difference is where your code runs. On the host, you code is running on the computer’s processor and doing floating point calculations.  If you target a LV FPGA target, your code is running in the FPGA.  In this case, you code must all be fixed point.  

You can probably do either method for your application.  Do the AM modulation on the host computer and create the IQ data that you transfer to the IF-RIO’s FPGA to generate with an IF-RIO DAC.  Or transfer your baseband waveform to the FPGA where the modulation is preformed.  You’ll also have to write fixed point LV FPGA code to control the AM adjustments you have in the Vis in your other post.

I’m not sure what your knowledge level is in terms of LV FPGA and LV FPGA targets. If you do a search on our web page, you can find a few tutorials on LF FPGA.

Jerry

[sandeep palreddy]

hey rajesh, my email is sandeep.palreddy@gmail.com. email me, i will see what i can do to help you. Hope to hear from you soon.