USRP 2955 Not Receiving Signal

[krmills]

Hello,

I'm very new to LabVIEW, and I'm working with 2 NI-USRP devices (2920 and 2955).

To test the receive/ transmit capabilities, I used the example VIs "niUSRP EX Tx Continuous Async" and "niUSRP EX Rx Continuous Async" using only the 2920 device. This works perfectly fine.

To then test the receive capability of the 2955, I edit the "niUSRP EX Rx Continuous Async" front end to select the appropriate device name, active antenna, and enabled channel for the 2955, while the "niUSRP EX Tx Continuous Async" is still set to the 2920. However, I only get noise. In fact, if I set the active antenna and enabled channel (of the Rx VI) to one that has no input, the waveform graph shows the same results as that with an input.

I should mention that the Tx and Rx of the hardware are connected with a sma cable and there is a 30dB attenuator connected to the Rx channel.

I included screenshots of the VI front ends for three cases: 1) 2920 transmitting to 2920 (itself) (2929to2920.png); 2) 2920 transmitting to 2955 (VI front end receive channel set to the hardware connected channel) (2929to2955active.png); and 3) 2920 transmitting to 2955 (VI front end receive channel set to a hardware disconnected channel) (2929to2955inactive.png).

Does anyone know why the 2955 device seems to receive no signal? 

Thank you for assistance!

[AgentAstronaut · Accepted solution]

Try the niUSRP EX Rx Multiple Inputs (Single Device, Multi Channel) example and see if that works for you. When you say you edit the front end do you mean you change some of the values on the front panel or are you modifying the example code?

Can you send a picture of your hardware setup? I want to check to see if your configuration matches your wiring.

Cheers,

Michael

[krmills]

Thank you Michael!

I tried the example you suggested. At first it didn't work, but then I removed the attenuator on my sma cable. There is screen shot (2920to2955-MultiChan.png) of the tx (2920) and rx (2955) front panels.

To answer your questions, by "front end" I meant the VI front panel, sorry for the confusion. I included a picture of my hardware setup (hardware-2920to2955.jpg), which shows the attenuator, if you're still interested.

I'm still not sure why the 2955 device wasn't working with the other example; more importantly, the 2955 wasn't receiving anything when using my team developed VI for a GNSS receiver. I hope to use niUSRP EX Rx Multiple Inputs (Single Device, Multi Channel).vi to make appropriate adjustments to my project. I will post updates here for anyone viewing this thread with similar issues.

Thank you again Michael!