Thanks for that. In order to track down this issue, I would like to ask: How often is a Ua printed ? Is it 1 Ua per error, or 100 errors, or is it arbitrary or dependant on when the code gets around to it ?
Regards. On 31 May 2018 at 00:36, Müller, Marcus (CEL) <[email protected]> wrote: > Hi Carlo! > > On Wed, 2018-05-30 at 23:04 +1000, Carlo Manfredini wrote: > > My hardware arrangement is fairly demanding, I think ? > > I wish to resample between a Red Pitaya connected via ethernet running > at 100kSps and a USB-audio unit (UCA-202) running at 48kSps. > > That's not "much signal to process"! In the context of SDR, we're often > considering dozens of Megasamples per seconds. > > > This code is simply a "loopback test" for both units running at once. > > Ha, I think that's the point here. > So, this sounds like the good ole' two-clock-problem: The rate of your > sound card is slightly different from 48 kHz, and the rate of your > Pitaya. But you do a perfect adaptation between 100 and 48 kHz. So, at > the end, one device has too many or the other too little samples per > second. > > > I would then add some signal processing to the signals in and out once I > have these working correctly. > > You can also see the break in the audio signal display in the time > sink...as well as the aUaUaU... > > When I view the PCs system monitor, it is using about 50% resources. > > > Perhaps the USB-based audio device is struggling to operate continuously > given that the RP is communicating via ethernet at about 1000kBps > (according to System Monitor). > > That's not really that much data, and you properly decimate that to the > rate your sound card can nominally do! > > > USB devices tend to be "bursty" and rarely operate continuously without > breaks when the PC has other tasks to attend to. > > Yeah, and something along these lines occasionally happens, because > talking to drivers is hard and GNU Radio's audio sink doesn't do that > in the best possible way, but really, the USB granularity doesn't lead > to discontinuities anywhere else, so why should it here? > > > A screenshot of the code is: https://drive.google.com/open?id= > 1XTNlHB87kNrX82cItMPWMvLGCGXvyr0U > > Thanks for any further suggestions. > > Maybe an option is to run the USB device at a slower sample rate ? > > Really, the amount of data isn't much here. You can use your system > monitor to see how much your CPU is utilized. It should be... limited. > > > Best regards, > Marcus
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