Can 2932 playback 25Msps 16bit complex IF samples

[zhe310]

I have some samples to playback. These files are recorded by 'RF record and playback system' NI PXI-5661 and NI PXIe-5672. I tried with the labview demo, it always report buffer overflow. And I am using SSD internal hard drive. Is there a way to playback the samples?

[warEagle12]

Hello!

Just to clarify your system setup, are you using the PXIe-5672 and downconverting the signal with the PXI-5661, streaming the data to disk, and trying to play back the signal using the USRP? What is the setup of your SSD hard drive and at what rate are you writing to the SSD? Typically buffer overflow is due a memory shortage within the system. 

Also, what playback VI are you using? I found this one online but I was not sure if it is the same as what you are using:

RF Record and Playback Reference Application: http://www.ni.com/example/30894/en/

Lastly, I found this white paper to introduce RF and Playback while I was looking in to this and it might have a few helpful pointers, though it might be too basic as well:

http://www.ni.com/white-paper/7209/en/

Thanks!

[zhe310]

Thanks for the response Stephanie,

The data is recorded using PXIe 5672 and PXI 5661 @25Msps with 16bits IQ to the hard drive. And I copied these data to my SSD, and try to playback these samples with niUSRP 2932.

The record and playback VI for usrp is

https://decibel.ni.com/content/docs/DOC-22174

If I try with 25Msps 16bits I/Q to playack, the VI will suddenly have no response after a few seconds. I am not sure if usrp could operate with such high sampling rate?

Thanks!

[Sarah_Y]

Hi zhe310,

25 Msps is the maximum possible sample rate for 1 Gigabit Ethernet with 16 bit IQ samples.  While in theory it is possible to get your USRP to operate at this rate, in reality it is difficult, especially on a Windows machine.  The buffer will overflow/underflow very easily at this rate since there is very limited on board memory.  There is a registry key you can modify to try and increase your system performance, but different Ethernet cards have varying performance and some might not be able to stream at the full rate of 25 MS/s.