NI-5781 Baseband Transceiver and NI PXIe-7962R (FPGA)

[dinesh07]

i am using keithley 2400 sourcemeter , using serial port rs 232 i connected with sourcemeter and i am writing a programm in labview to measure voltage or current when source voltage or current is given to sourcemeter respectively, error is coming while measuring so what command should i give to measure . i have attached my programm

[Air_Frantz]

Are you receiving a signal on the Rx end at all?  Were you able to get this working using the default created waveform instead of your modulated signal?

[josephkirmani]

Hi Jon F,

Thanks for your reply. Yes i am to receive waveform of the default getting started guide vi at the receiver side without having any problem. But I am not able to receive any signal on receiver side after modifying the original design with the modulated signal. I am able to see the waveforms of my modulated signal before "Host to FPGA write" in Analog output. But unfortunately I did not able to see it at the receiver side after "FPGA to Host read" in Analog Input.

[Air_Frantz]

How do you have the modules connected (ie cabling?), and do you see and sort of signal on the Rx end(possibly screenshot what you do see)?  I'm wondering if the issue appears to be with demodulating or if you are not seeing power in the bandwidth that you expect.

[josephkirmani]

The screen shot of Tx and Rx waveforms are attached for your reference. As you can see clearly at the transmitter side it shows the signal but on the receiver side just noise appears. 

[Jacobson-ni]

That definitely does just look like noise. Would you be able to attach the project which you have modified so we can take a look at exactly what you are doing? It is very possible that in trying to split up the code that some configuration steps were just loss but as Jon mentioned in his previous post, it is also possible that something just isn't connected correctly. Could you describe how your hardware is setup and how you physically have everything connected between the two FlexRIOs?

[josephkirmani]

Many thanks for your reply. Tx code is attached for your reference. In the receiver side right now I did not add any demodulation code. 

I am connecting Tx PXI with Rx PXI using MCX to MCX cable. Also if I connect oscilloscope at the output of Tx PXI using MCX to BNC cable. It also does not show anything and message appears on oscilloscope  "No Signal".

[Jacobson-ni]

Joseph,

What is the input impedence of your oscope and were you able to read the output signal using your oscope with the default project where everything seemed to be working? I also wanted to confirm that you did not make any changes to the FPGA code, I didn't see any changes but wanted to make sure.

I am assuming that you are not seeing any errors come up on the host but let me know if you are. The two things that I think you should try are, first, substituting back in the waveform generation of the original sample project to limit the potential sources of error. I would also recommend using a read/write node to check the stream.state 2 during execution.

[josephkirmani]

Hi Matt J,

Many thanks for your reply. The input impedance of my oscilloscope is 1Mohm and using the default project oscilloscope successfully displays the waveform without having any problem.

When I am running the code there are no errors in Host vi and I am using original FPGA vi file without any changes. 

But I am able to make it work. In my design I was previously taking the output directly from the waveform but instead if I use original create waveform vi last part where the "Scale waveform data to DAC codes" then my design works. I am able to see the waveform on Oscilloscpope and on Rx PXI too. But it gives me nearly 10MHz of signal so can you guide me is it related "Scale waveform data to DAC codes" or something else. Also can you guide how can I control frequency and no of samples.