04-03-2012 04:44 AM
I got a USRP2 recently, so I test it witht the continus TX-Rx code with it. After burning the FPGA and firmware image into the SD card with the NI-USRP utility, I connect the USRP2 to labview 2011 with a gigabit cable and plug an antenna into the Tx/Rx connector on the RX2400 daughter board, and run the "niUSRP Rx Continuous Lab.vi" and "niUSRP Tx Continuous Lab.vi" on the same USRP2. However, the results that I got from the examples seem incorrect, but I don't know why.
The following pic shows the screenshot of the niUSRP Tx Continuous Lab.vi. I set the carrier frequency to 2.441G.
The following pic shows the screenshot of the niUSRP Tx Continuous Lab.vi
The above pic shows that no signal has been received.
To example the error, I use a 2.4G spectrum tool to monitor the spectrum, the following pic shows the spectrum before runnint the Tx example:
The following image shows the spectrum after running the Tx example, and the red circle shows the frequence of 2.441G. The image demostrates that the spectrum is very complex in the trammitted signal. However, according to the setting of the Tx.vi, there should be only one frequency in the spectrum. Can anyone tell me why? Is there any errors in the setting? Is my daughter board broken?
04-04-2012 01:14 PM
The NI-USRP driver will work with the USRP2, but it does not work with all daughter boards. Currently, only the WBX and XCVR2450 daughterboards are supported. This is not to say that it will not work with others, but it has not been tested and getting results such as you are seeing is not unexpected. This does not mean that there is a problem with your daughter board, it simply means that we have not developed the driver to work with it.
The reason that you are able to see something on the IP and frequency plots on the IQ Transmitter VI is because the data that is being sent to the USRP is also being sent to an indicator. It doesn't have any correlation as to what is actually being transmitted.