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From: | Simon Olvhammar |
Subject: | Re: [Discuss-gnuradio] RFNoc and data rates |
Date: | Wed, 23 Sep 2015 20:49:43 +0200 |
User-agent: | Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 |
Hello, Thank you for your answers.Yes we do alot of averaging to expose the signal, in some applications we even average over several months.
Could you elaborate on the internal precision that you mentioned?We are looking for a simple block that could do sum(FFT:s)/(Number of FFT:s) element-wise and output this as as stream. For example a input of 1000 FFT:s with 4096 channels will result in a output of 1 averaged FFT with 4096 channels. I dont think we would need a iir filter for this?
Regarding stream decimation block, if it makes one item out of n items then what kind of processing is performed on those items? A simple average sum(items)/numItems or something else? Maybe it's this block that i'm looking for.
Best regards Simon Den 2015-09-23 kl. 10:10, skrev Sylvain Munaut:
Hi,My question is, is this possible using current RFnoc blocks?, with for example an average block?One thing worth considering is the internal precision. I'm not familiar with the requirement for RA but I assume if you do a lot of averaging it's to get rid of the noise and dig out very weak signals. The current average block might not have enough internal precision for your needs and might need to be tweaked a bit.Also wondering if a 8k channel FFT block might be expected in RFNoc anytime soon?Most of the blocks currently assume that 1 vector / fft size = 1 packet. And packets have to fit within the MTU, so with 4 bytes per sc16 sample, that's 2048 which is the current limit. And I think even the internal RFNoC fifos are sized with this MTU size in mind. So for larger FFTs you'll need other mechanism to synchonize the FFT boundaries, like the EOB flag. Cheers, Sylvain _______________________________________________ Discuss-gnuradio mailing list address@hidden https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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