On Fri, Mar 18, 2022 at 12:32 PM Marcus Müller <mmueller@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 <mmueller@gnuradio.org
> <mailto:mmueller@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
<mmueller@gnuradio.org
> <mailto:mmueller@gnuradio.org>
> > <mailto:mmueller@gnuradio.org <mailto:mmueller@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