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Re: [Discuss-gnuradio] Problems with dvbt 8k 64QAM


From: CEL
Subject: Re: [Discuss-gnuradio] Problems with dvbt 8k 64QAM
Date: Thu, 15 Mar 2018 21:45:23 +0000

Juan,

overflows happen on the SDR hardware! No wonder you're not seeing them
when reading samples from a file... A file doesn't care how fast you
process it, whereas a SDR device needs your computer to process the
samples as fast as it produces them.

So, whatever CPU utilization you observe with a file is completely
irrelevant to the question whether your PC is fast enough to process
these samples in real-time. What counts is that the signal processing
throughput, including handling the hardware overhead, is above the
sampling rate for any but the shortest-term average.

Best regards,
Marcus

On Thu, 2018-03-15 at 22:33 +0100, Juan Antonio wrote:
> When I work with adv16.cfile my 4 cores work almost 100% but there is
> no ovwerflow and the constellations hook
> 
> When I work with a file recorded with gqrx of 8k 1/4 2/3 64 QAM my 4
> cores work at 50%, there is no overflow and the constellations do not
> latch. This same file reproduced with osmosdr sink is reproduced
> without any problem with a receiver of dvbt
> 
> When I work directly with the hackrf with a channel 8k 1/4 2/3 64 QAM
> there is a lot of overflow, the constellations do not engage and the
> cores work at 50%
> 
> I can think of two things:
> 
> Try with a file similar to adv16.cfile but 64 QAM (I do not have it)
> 
> And 2nd that there is some parameter in some block that does not
> correspond with 64 QAM
> 
> Best  Regards
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

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