ucsdsysnet / sparsdr

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PlutoSDR Sink block + Compressing Pluto Source block ? #15

Open tkpudgy opened 2 years ago

tkpudgy commented 2 years ago

Hello,

This time I would like to setup a loopback test send and receive a known set of packets using SparSDR. With your team's help, I have a good understanding of how to setup the receive side using the Compressing Pluto Source + Reconstruct blocks. For the transmit side, I figured I can place the generic PlutoSDR Sink block on the same flowgraph. To start I just used the Signal Source block to create a tone and sent it to the PlutoSDR Sink block. I have tried many different parameter variations but I'm still unable to have any success. It's resulting in various RunTime errors. Do you have any suggestions on how to quickly setup a simple loopback test? Thank you!

samcrow commented 2 years ago

I have tried transmitting and receiving at the same time, so I can give some suggestions.

The compressing Pluto source will create one IIO context, and the regular Pluto sink block will create another. This should not cause a problem.

The compressing Pluto source sets the Pluto's receive sample rate to 61.44 MHz. I have had success when the transmit sample rate was also set to 61.44 MHz. With a different transmit sample rate, I got confusing runtime errors. It looks like the receive sample rate has to be equal to the transmit sample rate, or half of the transmit sample rate.

Setting the transmit sample rate to 61.44 MHz or 30.72 MHz might solve your immediate problem. 30.72 MHz might need a modified Pluto image, and either of those might exceed the capacity of the USB connection. It might be simpler to use a different device to transmit.