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Zedboard FMCOMMS2 GNURadio Data Dropouts

Question asked by austinsteamboat on Feb 20, 2015
Latest reply on May 19, 2016 by phenry

I'm using the Zedboard with an FMCOMMS2 radio module. I was able to load the Analog Device's version of GNURadio onto the Zedboard as well as onto a laptop to stream data from the Zedboard to the laptop. I've been trying to save raw IQ data for off-line algorithm development, and I've noticed that both on the Zedboard and the laptop, the data stream has a lot of dropouts, that is the data is sampled at the correct rate, but only a fraction of the total data I expect is written to disk. The explanation for the Zedboard is fairly straightforward as the SD card limits write speeds, but the same data dropouts were observed on the laptop even at the slowest specified data rates (and using a wired Ethernet connection between the two). I saw in some of the IIO documentation that there is ring buffer support, so I wouldn't expect data dropouts like this. Is this expected behavior?

 

I've also had issues on transmit using the GNURadio FMCOMMS2 transmit module. I found that when the cyclic option is not specified in the transmitter, only the first buffer of data is played out. When cyclic is specified, the first buffer is played out and repeated, so no new data can ever be played out. I strongly suspect this is not expected behavior, so has anyone seen this as well, or does anyone know what might cause this?

 

I'm using a 3.14 kernel build with generally a stock linaro file system. I have a slightly out of date version of ADI's GNURadio on the Zedboard and the latest version of ADI's GNURadio on the laptop. Any help would be greatly appreciated.

Thanks,

-Austin

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