Just as a heads up, someone mailed this into the mailing list the other
day. I think it accomplishes exactly what you all want -- although it
doesn't use PFBs as I recall.
https://github.com/madengr/ham2mon
- Tim
On Sun, Aug 2, 2015 at 2:18 PM, John Ackermann N8UR <address@hidden
<mailto:address@hidden>> wrote:
Hi Chris --
Using the variables, I now have the program working in general.
The channel mapping gave me some nightmares, though. I finally
decided that you need two maps -- one for the channelizer block,
where you do the 4,5,6,7,0,1,2,3 translation, and another for the
GUI that is a simple 0..7.
With that, it seems to be working well although my WBX front end
seems to have been fried as it is more deaf than it used to be.
Time to switch to hardware troubleshooting mode...
Thanks, again!
John
----
On 08/02/2015 12:10 AM, Chris Kuethe wrote:
Thanks for pointing out the paste-o. I'll fix that.
I'm using gnuradio 3.7.8rc1, which has helper blocks for computing
filter taps. You can replace them with variables:
pfb_taps = firdes.low_pass(2.0, oversampled_width, noaa_fm_dev * 2,
2500, firdes.WIN_HAMMING, 6.76)
lpf_taps = firdes.low_pass(1.0, hardware_rate, noaa_band_width / 2,
noaa_chan_width, firdes.WIN_HAMMING, 6.76)
On Sat, Aug 1, 2015 at 5:00 PM, John Ackermann N8UR
<address@hidden <mailto:address@hidden>> wrote:
Thanks much for this, Chris! I look forward to playing with
it, but...
When I load the flowgraph on my GRC 3.7.6.1 system, I get a
"Missing Block"
error for each of lpf_taps and pbf_taps, triggering errors
in the xfft and
channelizer blocks.
I also had an error in the "Multiply Const" block coming out
of channel 7.
but that was caused by a missing space before "else" in the
evaluation.
Help?
But thanks so much for taking this on. It's the perfect
starting point for
some projects I've been wanting to work on!
John
----
On 08/01/2015 03:26 PM, Chris Kuethe wrote:
OK, Here it is... at least, a beta version. I have yet
to come up with
a concise explanation of the channel map and why you'd
want to
oversample, but it is functional.
This flowgraph would work equally well by directly
connecting all the
ports together, but I'm a big fan of using virtual
sources and sinks to
make the design somewhat self-documenting..
On Sat, Aug 1, 2015 at 4:55 AM, Markus Heller
<address@hidden <mailto:address@hidden>
<mailto:address@hidden <mailto:address@hidden>>> wrote:
Great! Thanks! I'm very curious!
br/vy73
markus
dl8rds
Am Freitag, den 31.07.2015, 14:34 -0700 schrieb
Chris Kuethe:
> OK, I have a mostly working flowgraph and am
now adding comment
to all
> the blocks explaining why I'm doing this or
that. Will publish
tonight
> or tomorrow.
>
> On Tue, Jul 21, 2015 at 11:56 AM, Chris Kuethe
<address@hidden
<mailto:address@hidden>
<mailto:address@hidden
<mailto:address@hidden>>> wrote:
> > Maybe I'll do up an illustrated example on
this using NOAA
weather
> > radio, or the pager band
> >
> > On Tue, Jul 21, 2015 at 11:42 AM,
<address@hidden <mailto:address@hidden>
<mailto:address@hidden
<mailto:address@hidden>>> wrote:
> >> I just use the built-in firdes stuff, rather
than using an
external
> >> designer.
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> On 2015-07-21 14:38, Marcus Müller wrote:
> >>
> >> Hi Rich, hello Markus,
> >>
> >> On 21.07.2015 19 <tel:21.07.2015%2019>
<tel:21.07.2015%2019>:51, Richard Bell wrote:
> >>
> >> GNU Radio has channelizers built-in, but
I've not used them
yet, so I don't
> >> know how far they take you into this kind of
task.
> >>
> >> the Polyphase channelizer is actually an
implementation
derived from that
> >> school of thought, and it works amazingly well.
> >> In fact, in preparation of a presentation at
a certain ham
conference, I
> >> tried using it to get 20 PMR/LPD channels
out of a 1MS/s
signal in real
> >> time, and then just shuffle them around,
before feeding them
back into the
> >> inverse synthesizer PFB.
> >>
> >> It's pretty easy:
> >> Design a single low pass filter, as if you
just wanted to
filter out the
> >> channel which is centered exactly at your RF
center frequency,
i.e. 0Hz,
> >> with the full sampling rate [2], using the
gr_filter_design
tool. Play
> >> around with the different window types[1],
and bear in mind
that the
> >> suppression outside your desired passband
needs to be high
enough so that
> >> the sum of the energy in all other channels
don't hurt your
channel too
> >> much, but don't overdo it (60dB suppression
should be enough).
> >> Now you get a long filter. Copy and paste
the filter
coefficients from
> >> gr_filter_design to your PFB filter taps
property.
> >> Set your channelizers number of channels
according to your
plans -- 40, if
> >> you want to get all the 40 25kHz channels in
2MHz. You get a
block with 40
> >> outputs!
> >> Explaining things like channel mapping is
best done by
pointing you at the
> >> official documentation: [3]
> >>
> >>
> >> Greetings!
> >> Marcus
> >>
> >> [1] Hamming is not always the best choice,
I'd try that,
Blackman-harris,
> >> and Kaiser. I personally like harris in this
case -- we want
to get a full
> >> channel, two adjacent channels are usually
not occupied, and
as soon as we
> >> pass the stopband frequency, we're basically
at -100dB.
> >> [2] assuming you want to use 2MS/s for your
2MHz wide band,
2MHz sampling
> >> rate, and assuming 25kHz wide channels,
12.5kHz cut off
frequency, 25kHz
> >> start of stoppband. I get something like 440
taps.
> >> [3]
> >>
https://gnuradio.org/doc/doxygen/classgr_1_1filter_1_1pfb__channelizer__ccf.html
> >>
> >> _______________________________________________
> >> Discuss-gnuradio mailing list
> >> address@hidden
<mailto:address@hidden>
<mailto:address@hidden
<mailto:address@hidden>>
> >>
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >>
> >>
> >> _______________________________________________
> >> Discuss-gnuradio mailing list
> >> address@hidden
<mailto:address@hidden>
<mailto:address@hidden
<mailto:address@hidden>>
> >>
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >>
> >
> >
> >
> > --
> > GDB has a 'break' feature; why doesn't it
have 'fix' too?
>
>
>
--
GDB has a 'break' feature; why doesn't it have 'fix' too?
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