I've never used it for RF work, but pandas is a very powerful framework for
working with timeseries and multi-dimensional data.
Very Respectfully,
Dan CaJacob
On Wed, Jul 16, 2014 at 11:20 AM, Marcus Müller <marcus.muel...@ettus.com>
wrote:
> Hi Peter,
>
> GNU Radio is based very much on the idea of a data stream, so it might
> not actually be the tool of choice for static analysis.
> However, there is quite a lot which can be done with on-board tools, so
> let me comment in-text.
> On 16.07.2014 16:52, Peter A. Bigot wrote:
> > GNU Radio is a great tool for applications and dynamic
> > experimentation, but it doesn't have a lot of support for
> > static/offline analysis of time-series data. I.e. I've captured some
> > signal data and I want to explore its properties interactively so I
> > can figure out what I want to do with it in GNU Radio.
> >
> > The sort of capabilities I'm looking for include:
>
> > Read time-series data from files of different formats (some too large
> > to fit in physical memory).
> So far, only raw samples in machine float format are supported, and the
> GNU Radio-specific metadata/samples interleaved format along with the
> Wav audio file format. As far as I know, all of the sources/sinks for
> these file formats don't need to store data in RAM but read/write it
> sequentially.
>
> If you feel like there is something obviously missing in this list, you
> could just use the awesome powers of python and/or C++ to read your
> favourite file format, write a database adapter or a twitter source; the
> reason we don't have things like native CSV or HDF support is that I
> guess noone cared to implement a source for these formats, because they
> don't lend themselves to streaming very well, and not because it's hard.
>
> Anyway, there's a series of small tools for sample files, called
> gr_{plot,plot_fft,spectrogram}_<type>, that at least allow you to
> visualize recorded data easily, included in GNU Radio.
>
> > Display the data, optionally applying linear transformations.
> Well the problem here is that our visual sinks usually want to
> periodically update the display, and that GNU Radio flow graphs usually
> terminate when sources have finished producing items (e.g. when the
> source file has been read completely). Many of these issues can be
> worked around be setting your file source to repeat and "pausing" the
> graphical sink when you see something interesting, after throttling your
> item flow enough to make the signal observable by the naked eye.
>
> The linear transformation thing is something you'd have to implement in
> a DSPish manner, and most probably can be done.
> > Interactively pan and zoom.
> Most of the graphical sinks can do that
> > Jump forwards and backwards among time-registered events.
> Nope, I'm afraid that won't work with the stream-oriented architecture
> of GNU Radio.
> > Enable/disable/time-shift data overlays.
> Again, if you feed a graphical sink with a signal and a time-shifted
> version, you get a DSPified method of doing your visualization
> > Export selected data to new files.
> not really available (yet?).
> > Calculate and display statistics and other non-linear transformations
> > of selected data.
> Depends. Again, if you can translate your statistics to a signal
> processing algorithm, then it's almost certainly already been done or is
> "easy" to do.
> >
> > Ideally I'd like an open-source analysis framework that I can extend
> > in Python or C++; something like the Midas DSP tool family.
> Not aware of these, sorry, and google turned up some defense program
> along with large audio mixers. Do you have a URL to refer to?
> > I'm aware of some Qt widgets like QtCustomPlot, and generic frameworks
> > like matplotlib and octave, but not of any ready-to-use applications
> > or frameworks that already provide the basic functionality described
> > above.
> I think you should take a look at things like R, GNUplot etc.
> Anyway, this is a very interesting topic, and I would really enjoy
> hearing from cool software that does what you describes in a manner that
> could e.g. be explained to EE first-semester students or so.
> > The keywords I've tossed at Google haven't produced any obvious
> > solutions, and discussions I find in the archives here are a couple
> > years old and seem to summarize as "use maplotlib/octave".
> I'm afraid my 2014 reply will disappoint you a little... it's "if you
> know what characteristics you're looking for, go for a few lines of
> python; if you don't know, go for python and some additional lines".
> Actually, I've grown so used to numpy/scipy/matplotlib/pyqtgraph that I
> wouldn't trade it for Matlab (I have access to that and rarely use it),
> especially because python is something I would consider a real language
> whereas the matlab syntax and the matlab interpreter performance...
> well, matlab has fantastic documentation.
>
> >
> > Is any such framework available now or in development? If not, is
> > anybody interested in joining me offline to discuss the requirements
> > and design for such a thing?
> Count me in, as this is relevant to my work.
>
> Greetings,
> Marcus
> >
> > Thanks.
> >
> > Peter
> >
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