On Fri, Mar 18, 2022 at 12:32 PM Marcus Müller
<mmuel...@gnuradio.org> wrote:
Ah cool! Thanks for clarifying :) This sounds to be a rather
nice setup, analog-wise!
Yeah, then just dumping the raw 32bit unsigned to SD Card is
probably easiest.
(by the way, this is << 1Mb/s, so just dumping the raw data
over a UART or SPI interface
to some serial-to-USB converter might work as well to get the
data into your PC. If your
ARM does have USB2 built-in, then that would also be a rather
cool thing, but knowing the
varying quality of chip vendor USB hardware abstractions,
that might or might not be easy
to implement :) In both cases, UART/SPI serial output
converted to USB, or native USB,
you'd probably have to afterwards write a schmall C/C++
driver, so that SoapySDR or GNU
Radio directly can talk to it.)
Cheers,
Marcus
On 18.03.22 19:26, david vanhorn wrote:
> I'm using a PCB that I designed with an ARM chip, codec,
and SD card for logging, as my
> data capture platform.
> Feeding that is a QSD (Tayloe) front end that I designed,
specifically for the 630m ham
> band, converting down to 1kHz differential I and Q signals
to the codec, which has a 105dB
> SNR.
> The front end appears to have a 90dB linear dynamic range
so far as I can measure with my
> equipment. I'll improve that if I can.
> Once I capture to SD, then I can pull the SD and process on
the PC to develop weak signal
> detection.
>
>
>
> On Fri, Mar 18, 2022 at 12:12 PM Marcus Müller
<mmuel...@gnuradio.org
> <mailto:mmuel...@gnuradio.org>> wrote:
>
> Hey :)
>
> CSV might or might not be convenient, but if C or
assembler is your tool: The things that
> the GNU Radio file source reads or the file sink writes
is exactly what you get when you
> take a buffer of samples and do an `fwrite` on that :)
Just a dump of the raw memory to a
> file. 32 bit unsigned should be directly digestible by
GNU Radio (even if there were
> endianness issues – you can just read as bytes and
reshuffle as needed :)).
>
> I didn't fully get how you're currently interfacing
your hardware. Care to explain in a
> bit more breadth? What are the components of your
system, and how does the computer
> running GNU Radio relate?
>
> Best and slightly excited regards,
> Marcus
>
> On 18.03.22 18:37, david vanhorn wrote:
> > Hi!
> >
> > I'm trying to interface some radio hardware I built
to GnuRadio by way of data
> captured to
> > SD cards.
> > I have two channels (I and Q) of 32 bit unsigned
data internally, and I originally
> assumed
> > CSV would be the easy path, but now I see it's not.
> > Coming in through the PC sound card is not an option
for me, I'm using a particular
> codec
> > selected for the application, and my goal is to
develop signal processing
> algorithms to
> > then be implemented back on my processor in C or ASM.
> >
> > I suppose it would be easiest if I rework my
hardware to log data as if it were the
> > "Signal Source" block with complex output.
> > Where can I see what that looks like at the level of
raw data?
> >
> >
> >
> >
> > On Fri, Mar 18, 2022 at 4:59 AM Marcus Müller
<mmuel...@gnuradio.org
> <mailto:mmuel...@gnuradio.org>
> > <mailto:mmuel...@gnuradio.org
<mailto:mmuel...@gnuradio.org>>> wrote:
> >
> > Hi David,
> >
> > you could write a quick python block that just
reads values from the CSV file
> and outputs
> > them. That'd be a very nice, basic exercise, and
I think our freshly overhauled
> > tutorials[1] should bring you there very quickly!
> > If you want help with that, hit us up in this
mailing list (ideally after
> reading the
> > tutorials up to the point of roughly
understanding how to write (embedded) Python
> > blocks),
> > and tell us more about the data in your CSV files.
> >
> > Alternatively, you could also write a converter
of CSV to a format that GNU
> Radio by
> > itself already has a reader for – and the main
candidate here would probably
> just be
> > plain
> > raw data files (as e.g. numpy's
`ndarray.tofile("filename")` does) – the File
> Source
> > could
> > directly read that. But with our freshly rewrite
Wavfile sink and source
> blocks, we can
> > write and read most audio files, just as well.
> >
> > Then your flow graph could do the signal
processing you want – e.g frequency
> translation,
> > low-pass filtering… and finally output it to any
device that you have a GNU Radio
> > interface to (e.g., your sound card). The
hardware runs at a sample rate – GNU
> Radio
> > itself just tries to feed it as fast as
possible. So, the signal processing in
> GNU Radio
> > itself isn't concerned with rate at all!
> >
> > Hope this helps,
> > Marcus
> >
> > [1] https://tutorials.gnuradio.org
<https://tutorials.gnuradio.org>
> <https://tutorials.gnuradio.org
<https://tutorials.gnuradio.org>>
> >
> > PS: you'll often find me online, recommending
not to use CSV as a sample
> storage format.
> > I'll do the same to you here, but not because I
think it's in any way invalid
> to have
> > data
> > in CSV files; I just want to point out it might
be worth thinking about using
> something
> > else. So take this with a "I think it's pretty
cool you're doing this!".
> >
> > That has the reasons that
> > a) unless you're more restricted than "CSV"
says, you don't know how many bits
> are there
> > per sample, as numbers might be represented in
different lengths, so seeking
> exactly only
> > works by reading and understanding the whole
file up to the point you seek to,
> > b) conversion of floating point numbers to
human-readable form incurs rounding
> errors,
> > and
> > that can really wreck your day if you need to
rerun *exactly* the same
> experiment twice,
> > c) printing numbers as text is really
inefficient, both storage-wise as well as
> compute
> > wise (which will only matter at higher sampling
rates) and sometimes, but only
> sometimes,
> > ( d) people say that CSV is good because it's
human-readable, but I challenge
> anyone to
> > read a text file with only 10000 values and be
happier about that than if he
> used a tool
> > that displayed the values graphically, zoomably,
and then allows for inspection
> of single
> > values once zoomed sufficiently in.)
> >
> >
> > On 18.03.22 04:55, david vanhorn wrote:
> > > I've done a little with Gnuradio a couple
years ago, but I'd now like to
> apply it to a
> > > serious problem.
> > >
> > > I have a design I'm working on that will
output raw data that could be
> interpreted
> > as an
> > > audio stream centered on 1kHz. I'd like to
work on extracting CW signals
> that are
> > rather
> > > slow, from a rather narrow bandwidth, and see
how far down into the noise I can
> > actually
> > > extract the signals.
> > >
> > > Is there a block that can bring in CSV data
from a file at a specific rate, and
> > serve as
> > > the input to my CW detection system?
> > >
> > >
> > > --
> > > K1FZY (WA4TPW) SK 9/29/37-4/13/15
> >
> >
> >
> > --
> > K1FZY (WA4TPW) SK 9/29/37-4/13/15
>
>
>
> --
> K1FZY (WA4TPW) SK 9/29/37-4/13/15
--
K1FZY (WA4TPW) SK 9/29/37-4/13/15
