[Back on list - my goof] On Thu, Aug 12, 2021 at 7:50 AM Kristoff <[email protected]> wrote:
> Jeff, > > > Thanks for the very quick reply. > I don't know if you intended to reply just to me, or to the list. > > Feel free to forward to the list if you want. > > > Well, let's take the example of HFDL. > From what I have found, it's a packet of data that starts with a tone > (to allow the receiver to correct any frequency-offset), and then a > burst of data in BPSK, QPSK or 8PSK @ 1800 baud. > > I guess, if you want to decode this, you > - first need to detect the start of the 'frequency-tone' > - measure any frequency offset of that tone > - multiply the rest of the packet with a tone at -x Hz > - then to PSK demodulation. > I am not sure of the PSK order is encoded in a header or so, so I guess > that you just have three decoders running in parallel and see which one > returns a valid bitstream. > > > It would be nice to do this one manually, so I can really inspect the > packet. > But I guess that if you would want to automate this (i.e. write a GR > demodulator block for this), then you need to write a python script that > implements this. > > For that, I guess I need to learn what library (numpy, scipy-signal, > commpy, ... ) does what. > (I have the impression that these libraries overlap) > > > > > Note. > I do not know if there are already HFDL decoders in GR. For me, this is > just an exercise to learn how to do this. > > And I think that HFDL is probably one of the less difficult protocols to > decode so it looks like a good place to start. > (just guessing here). > > > > > Kristoff > > > On 12.08.21 13:27, Jeff Long wrote: > > That's a good list. Is there some specific capability you are looking > > for? > > > > Baudline is an older tool, but is still useful for looking at files in > > a little more detail than Inspectrum. > > > > You didn't mention URH https://github.com/jopohl/urh > > <https://github.com/jopohl/urh> > > > > On Thu, Aug 12, 2021 at 7:15 AM Kristoff <[email protected] > > <mailto:[email protected]>> wrote: > > > > Hi all, > > > > Does anybody have a list of good python resources for "non-real-time" > > signal-processing of radio-signals. > > ("non-real time" as in "an iq-file of prerecorded dataframe", in > > contrast a continuous stream like a GR flowgraph) > > > > > > > > Say you start with the IQ-file of a HFDL-packet and you would want to > > analyse and visualize it, take it apart, demodulate and decode it, > > etc. > > > > > > I've come across libraries like numpy, scipy-signal and commpy, > > visualization-tools like matplotlib and seaborn and others. > > > > For audio, there is off course audacity. > > For quick-and-dirty visualization of radio-packets, I have used > > inspectrum. > > > > > > So there does not seams to be a lack of tool, .. perhaps there are to > > many of them :-) > > > > It would be nice to have a overview of what tools/libraries are > > available to do what, and what would the good method to build a > > 'flow' > > to -say- build a GR block for a HFDL packet decoder. > > > > > > > > I have already found pysdr.org <http://pysdr.org> to be an > > interesting resource. > > > > Anybody an idea of other resources? > > > > > > > > > > >
