Remote streaming with X410 and CG_400 firmware - unexpected start of IQ data position in packet

[mfennell]

I've been seeing odd results (high noise floor, poor signal quality) when remote streaming from an X410 with the CG_400 firmware. I finally captured some packets and discovered that there are 48 bytes of zeros between the 16 byte header and actual data. The data packets include 1984 samples rather than 2000 the CHDR length of 8016 implies. I'm hoping someone can confirm this is expected. I've not encountered it in any documentation.

Also, will the X440 behave similarly on CG_1600?

[mfennell]

Does anyone have any technical contacts I might approach? I'd appreciate some confirmation on this. Unless I'm missing something (which is entirely possible), the CG_400 firmware does not conform to the RFNoC standard when performing remote streaming.

Thank you,

Mike

[mfennell]

If anyone ever sees this - I confirmed with NI technical support that the 48 bytes of zeros is additional reserved header space. It sounds like this change will occur with all new firmware releases. I'm not sure if that indicates an expectation to update the RFNoC specification or not.