Hello Juha, idea: if Dave's distribution of amplitudes was a little more benign than the Radar near/far problem, and he would favor full resolution when the signal is weak, but could live with a bit of degradation due to quantization when the signal is strong, what about storing a logarithm of the I and Q magnitudes instead of their linear value? That way, he could get the same weak-signal-resolution with less bits, and only suffer inaccuracies due to quantization for situations where signal is strong, anyway.
Best regards, Marcus On 16.07.2016 21:57, Juha Vierinen wrote: > Can you reduce the number of bits that you are using? > > With radar signals, the receiver noise most of the time excites only > about 8 bits out of 16. Ground clutter or meteor echoes excite nearly > all of the bits occasionally, so I can't just truncate to 8 bits. In > this case, bzip2 actually does a pretty good job of getting rid of the > 8/16 most significant bits that are zero most of the time. Thus, I get > a compression ratio close to 50% when using sc16. pbzip2 is a good > tool for doing parallel compression on files. > > juha > > On Sat, Jul 16, 2016 at 3:59 AM, Dave NotTelling <[email protected] > <mailto:[email protected]>> wrote: > > Anyone have experience with streaming 100+ MSPS of 16 bit IQ data > through a compression tool and then to disk? I'd like to be able > to take really wide band snaps for several minutes. Currently > that would take up 16 * 2 * SAMP_RATE bits per second. So, for > 200 MSPS that would end up being 800 MBytes/s. That rate eats up > a hard drive pretty quickly. Running it through gzip by way of > pigz was my first thought, but even on an 8 core Intel machine > pigz just can't keep up. I can sustain maybe 300 MBytes/s but > that's it. And I know it's not a hard disk limitation as the M.2 > drive I am using can easily sustain 800 MBytes/s of uncompressed > data. > > Thoughts? > > Thank you! > > > -Dave > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] <mailto:[email protected]> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
_______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
