Re: [Discuss-gnuradio] Streaming IQ File Compression

Marcus, Thanks for the idea anyway :) It sounded like a really neat outside the box idea. I ran some quick tests with FLAC and found that it does a really good job compressing a constant filtered gaussian noise output. I just created a flow graph with: fast noise source [float] ->

Re: [Discuss-gnuradio] Streaming IQ File Compression

Well, having wasted a couple of hours of sleep time on this, maybe you shouldn't do the logarithmic storage... at its core its the same idea as storing floating point, but with a fixed mantissa. The mathematical effects of the "rounding to the nearest exponential step" on superimposed sinusoids

Re: [Discuss-gnuradio] Streaming IQ File Compression

Chris, Excellent, then I will start benchmarking tomorrow :) Thanks! On Sat, Jul 16, 2016 at 9:35 PM, Chris Kuethe wrote: > Flac doesn't really need to know what the actual sample rate is; you > could tell it 500e3 and you should get the same data out after >

Re: [Discuss-gnuradio] Streaming IQ File Compression

Flac doesn't really need to know what the actual sample rate is; you could tell it 500e3 and you should get the same data out after compressing and decompressing it. On Sat, Jul 16, 2016 at 11:20 AM, Dave NotTelling wrote: > Marcus & Dan, > > Thank you very, very much

Re: [Discuss-gnuradio] Streaming IQ File Compression

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

Re: [Discuss-gnuradio] Streaming IQ File Compression

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

Re: [Discuss-gnuradio] Streaming IQ File Compression

Marcus & Dan, Thank you very, very much for the detailed information! Dan: That's exactly what I thought when going into this at first. But, I decided to give gzip a shot just to see how well it did. Turns out that (at least for bursty environments) it almost halves the size of the

Re: [Discuss-gnuradio] Streaming IQ File Compression

Ah! On 16.07.2016 11:04, Marcus Müller wrote: > and maybe, but this is really speculation, you can just modify the > error calculation to just ignore the 4 lower bits of the actual sample > data, and safe another few percents of data volume. Yeah, there's a

Re: [Discuss-gnuradio] Streaming IQ File Compression

> If there's a lot of white noise, you won't get much compression Alas, Entropy is killing compression. So yeah, if you anyhow can, try to reduce bandwidth by filtering and decimating. You can also just "round" or even "throw away" bits – at 100MS/s (presumably coming from a X310 running at a

Re: [Discuss-gnuradio] Streaming IQ File Compression

You'll likely have to buffer the output to a ramdisk and then slowly bleed that to the disk. Compression typically doesn't work well on IQ data unless you've got a structured signal in there. If there's a lot of white noise, you won't get much compression On Sat, Jul 16, 2016 at 12:00 AM Dave