[Discuss-gnuradio] Best path forward for transmitting canned waveforms from N310 / X310

[Lundberg, Daniel]

A bit of background:

I have been using a B205i mini to transmit a variety of canned waveforms.  These have ~5 MHz of BW, and I’ve been using binary files sampled at 6.25 MS/s.  I use a modified version of the tx_samples_from_file example, using a host laptop via a USB 3.0 to Ethernet adaptor.  The manner in which it is operated allows the process to be slow, i.e., it’s OK for me to manually launch a new script that selects a different waveform binary file on the host laptop each time I want to start transmitting something else.  This all works fine. 

 

However, the quality of the waveform is important, and the b205 has some noticeable limitations with respect to IQ imbalance resulting in unwanted amplitude modulation, phase noise, a 12 bit DAC, etc…  This is OK, because it is a <$1000 device, but now it’s time to do better.  I have an N310 to try, and I am looking for feedback on the best path forward.  I understand that the clock rate selections are somewhat limited, but that I should be able to run it in a comparable way to the B205 if I allow the N310 to perform interpolation, i.e., 125 MS/s with an interpolation factor of 20.  This is an OK first step.

 

So now to my question:

I would like to investigate the transmit quality without the N310’s interpolation, because I have no idea exactly how it does this signal processing.  So the path forward there is to set up an interface on a host that can stream at 125 MS/s, which is not trivial (thunderbolt adaptors, PCIexpress, etc…).  I am curious if it is possible for me to run the N310 in embedded mode, have the waveform files loaded locally on the N310, and issue commands to transmit in a loop.  These files are currently ~80MB each, because they are ~1.5 seconds sampled at 6.25 MH/s.  They would scale up to ~1.6 GB if sampled at 125 MS/s with no interpolation.  Is this something the N310 hardware could handle in embedded mode, i.e., streaming from its own hardware resources, rather than through the SFP?  I am finding documentation on the embedded mode of the N310 hard to find, but I may just be looking in the wrong places.

 

Thank you,

Dan