[Discuss-gnuradio] lack of clarity regarding "FM wav file" (was: Re: Discuss-gnuradio Digest, Vol 176, Issue 29)

[Marcus Müller]

Hi Mattipa,

I know this is kind of annoying, but the first actual line of text in
the mail you replied to is:

> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Discuss-gnuradio digest..."

I'd politely ask you to try and adhere to such advise (as it gets hard
to follow conversations if you don't).

In any case, if *you* can't guess what you professor meant, then how are
*we* supposed to guess? If in doubt about what a task entails, ask the
one who assigned that task to you, not someone on "the internet". We
really can't guess what's inside a file you've been given.

Best regards,

Marcus


On 30.06.2017 07:15, Jahnavendra Mattipa wrote:
> Please bear my short message below,
> I am sorry Mr. Marcus, i know i asked some irrelevant and undefined
> questions. But this question is not mine, my scientific professor
> aksed me try to convert the FM wav file to I, Q values if possible. I
> also confused with that question and searched some papers too but no
> information regarding this.
>  Thank you Marcus.
>
> Best Regards,
> M. Jahnavendra
>
> On Thu, Jun 29, 2017 at 9:30 PM,  > wrote:
>
> Send Discuss-gnuradio mailing list submissions to
> discuss-gnuradio@gnu.org 
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> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Discuss-gnuradio digest..."
>
>
> Today's Topics:
>
>1. gr-eventstream, gr-mapper, gr-burst revisted (Cinaed Simson)
>2. [UHD] Introducing the Python API (Martin Braun)
>3. Convert recorded FM wav file to I,Q values (Jahnavendra Mattipa)
>4. Re: Convert recorded FM wav file to I,Q values (Marcus M?ller)
>5. query about fm example file in github tutorials repository
>   (Jacqueline.Walker)
>
>
> --
>
> Message: 1
> Date: Wed, 28 Jun 2017 14:58:55 -0700
> From: Cinaed Simson  >
> To: GNURadio Discussion List  >
> Subject: [Discuss-gnuradio] gr-eventstream, gr-mapper, gr-burst
> revisted
> Message-ID: 
> Content-Type: text/plain; charset=utf-8
>
> gr-eventstream:
> --
>
> In '_es_swig.so', instead of including the symbol 'init_es_swig' and
> linking to python2 libraries, it was including the symbol
> 'PyInit__es_swig' and linking to python3 libraries.
>
> See ./build/swig/es_swigPYTHON_wrap.cxx.
>
> Tried to modify the cmake file GrPython.cmake and GrSwig.cmake but
> couldn't stop '_es_swig.so' from including the symbol
> 'PyInit__es_swig'
> and linking to to python3 libraries.
>
> So I had to uninstalled libpython3-dev and it passed
>
>  make test
>
> gr-mapper:
> -
>
> Test failed because the cart got in front of the horse.
>
> In 'qa_preamble.py' I had to replace 'import mapper' with
> 'import mapper_swig as mapper' and then it passed
>
>  make test
>
> gr-burst:
> -
>
> Fails because 'qa_synchronizer_v3.py' because
>
>   x = sio.loadmat('../../matlab/gr_impl_test.mat')
>
> can't find the file 'gr_impl_test.mat' - which is typically a show
> stopper - there could be other errors.
>
> Couldn't find the file on
>
>   https://github.com/gr-vt/gr-burst/tree/master/matlab
> 
>
> either - and yes, 'scipy' is installed on the system.
>
>
> -- Cinaed
>
>
>
>
>
>
> --
>
> Message: 2
> Date: Wed, 28 Jun 2017 15:36:23 -0700
> From: Martin Braun  >
> To: "'usrp-us...@lists.ettus.com
> '"  >,
> "discuss-gnuradio@gnu.org
> "  >
> Subject: [Discuss-gnuradio] [UHD] Introducing the Python API
> Message-ID: <954eb77d-f574-aea4-25a7-956076e07...@ettus.com
> >
> Content-Type: text/plain; charset=utf-8
>
> Hi all,
>
> some people have already heard the rumour that we're working on a
> Python
> API for UHD that does not involve gr-uhd. And yes, it's true. A minute
> ago, I 

[Discuss-gnuradio] [GSoC 17] DAB: Updates of the week

[Moritz Luca Schmid]

Hi all,

this week is the first evaluation period of Google Summer of Code.

I started to work on my next milestones for the second coding period 
which mainly contain the audio encoding and decoding.


I also dealt with some buffer issues due to long vectors which lengths 
are no power of 2 bytes.


Read in detail in my latest blog post 
.



Best

Luca

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[Discuss-gnuradio] Backoff Counter in IEEE 802.11 impmelemntation

[Ayan Chatterjee]

Hi all,

Can a backoff counter be introduced to this implementation
https://github.com/bastibl/gr-ieee802-11 ?

Regards,
Ayan
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Re: [Discuss-gnuradio] dBm and dB Measurements

[Gilad Beeri (ApolloShield)]

Can you convert the data to a table + 2 graphs (1st: SA level vs. input
power, 2nd: SDR level vs. input power)? It will help you and others
conclude the relationship between the behaviors

On Thu, Jun 29, 2017 at 11:16 PM GNUBeginner  wrote:

> Hello Everyone,
>
> I am using HackRF One and running gr-scan spectrum monitoring software. I
> am
> also utilizing vector signal generator and spectrum analyzer.
>
> Can anyone please help me understand the following measurement results from
> both spectrum analyzer (reference level: -20 dBm) and gr-scan?
>
> Spectrum Analyzer: -25 dBm VSG at 2437 MHz -> Peak Power: -47.26 dBm
> (Almost
> no loss since it is one foot cable directly connected to spectrum analyzer
> from vector signal generator)
>
> gr-scan: -25 dBm VSG at 2437 MHz -> Peak Power: -47.61 dB
>
> Spectrum Analyzer: -30 dBm VSG at 2437 MHz -> Peak Power: -52.85 dBm
> (Again,
> it is the same...Almost no loss)
>
> gr-scan: -30 dBm VSG at 2437 MHz -> Peak Power: -51.37 dB
>
> Spectrum Analyzer: -35 dBm VSG at 2437 MHz -> Peak Power: -58.22 dBm
> (Almost
> no loss)
>
> gr-scan: -35 dBm VSG at 2437 MHz -> Peak Power: -58.34 dB
>
> Spectrum Analyzer: -40 dBm VSG at 2437 MHz -> Peak Power: -63.21 dBm
>
> gr-scan: -40 dBm VSG at 2437 MHz -> Peak Power: -63.15 dB
>
> Spectrum Analyzer: -45 dBm VSG at 2437 MHz -> Peak Power: -67.63 dBm
>
> gr-scan: -45 dBm VSG at 2437 MHz -> Peak Power: -67.41 dB
>
> I guess there is no relationship between SDR dB values and spectrum
> analyzer
> dBm values but what I have noticed that SDR is linearly following VSG power
> increments.
>
> Thanks,
>
>
>
> --
> View this message in context:
> http://gnuradio.4.n7.nabble.com/dBm-and-dB-Measurements-tp64413.html
> Sent from the GnuRadio mailing list archive at Nabble.com.
>
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Re: [Discuss-gnuradio] Backoff Counter in IEEE 802.11 impmelemntation

[Marcus Müller]

Yes!

Regards,

Marcus


On 06/30/2017 11:26 AM, Ayan Chatterjee wrote:
> Hi all,
>
> Can a backoff counter be introduced to this implementation
> https://github.com/bastibl/gr-ieee802-11 ?
>
> Regards,
> Ayan
>
>
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[Discuss-gnuradio] FW: Fwd: query about fm example file in github tutorials repository

[Jacqueline . Walker]

FWIW, I got the aforementioned "fm101.8_1Msps.cfile" to demodulate once I tried 
using the more generic FM demod block rather than the WBFM receive block.  I 
was using the rational resampler block in both cases to match the audio sink 
rate (48 kHz) and I did have the 'Ok to block' option turned off in the audio 
sink there too. I do have to go to some trouble to configure the audio for the 
ArchLinux VM I am using but it does work once I remember to  crank up the 
volume.

So the only change I made was to switch to using the FM demod block and then I 
could hear the demodulated fm sample file. I note that the FM demod block 
includes a LPF setting but I assumed that was present in the WBFM receive 
block? Anyway I was able to use the WBFM receive block successfully to 'listen 
to' FM radio received and streamed by a B200. Just a bit puzzled as to why it 
didn't work with the streamed data file.

Regards
Jacqueline

From: Discuss-gnuradio 
[mailto:discuss-gnuradio-bounces+jacqueline.walker=ul...@gnu.org] On Behalf Of 
Jacqueline.Walker
Sent: 29 June 2017 20:44
To: discuss-gnuradio@gnu.org
Subject: [Discuss-gnuradio] Fwd: query about fm example file in github 
tutorials repository



Sent from my HTC

- Forwarded message -
From: "Jacqueline.Walker" 
mailto:jacqueline.wal...@ul.ie>>
To: "Marcus Müller" mailto:marcus.muel...@ettus.com>>
Subject: [Discuss-gnuradio] query about fm example file in github tutorials 
repository
Date: Thu, Jun 29, 2017 8:40 P.M.

OMG, silly me ...it was staring me in the face as I was laboriously typing out 
the filename!!

Thanks will try that
Regards
Jacqueline

Sent from my HTC

- Reply message -
From: "Marcus Müller" 
mailto:marcus.muel...@ettus.com>>
To: "discuss-gnuradio@gnu.org" 
mailto:discuss-gnuradio@gnu.org>>
Subject: [Discuss-gnuradio] query about fm example file in github tutorials 
repository
Date: Thu, Jun 29, 2017 6:43 P.M.


Hi Jacqueline,

judging from the file name (_1Msps), the sampling rate is 1 MS/s. When it comes 
to signal bandwidth - a complex 1MS/s stream can contain up to 1 MHz of 
bandwidth, but FM broadcast radio stations typically use something like 75 kHz 
of bandwidth for their FM signal.

Best regards,

Marcus

On 06/29/2017 04:39 PM, Jacqueline.Walker wrote:
Hi,

I downloaded the file fm101.8MHz_1Msps.cfile (from 
gr-tutorials/examples/tutorial6/ ) to use for trying out demodulation 
flowgraphs in gnuradio. It was recommended here: 
https://wiki.gnuradio.org/index.php/Guided_Tutorial_Hardware_Considerations
But I can't find any details about the file - it says on the tutorial page - 
'an actual recording from a radio (USRP I presume) with nothing done to the 
data, so I presume it is just a binary stream such as one would receive from a 
USRP and that the centre frequency is 101.8MHz. What is the sample rate output 
by the USRP that recorded the file - is it 250k as given on the tutorial page? 
What is the signal bandwidth expected? I ask this because I don't see that much 
on the FFT?

Thanks
Jacqueline



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[Discuss-gnuradio] [GSoC 2017] gr-bokehgui: Updates on Week 7

[Kartik Patel]

Hello all,

This week, I added a Base Sink template class. It will be a common class
for all sinks. For more details, check out my latest blog post here
.

Thank you.

Regards,
Kartik Patel
ᐧ
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[Discuss-gnuradio] Problem processing BLOB type in a new block for IEEE 802-11 transceiver

[Cristian Rodríguez]

Hi all.

I'm trying to convert a variable from BLOB to String.

I'm trying to do this.

[image: Imágenes integradas 1]

Before, the next block was instead of WiFi App.

[image: Imágenes integradas 2]
Message strobe sends a PMT message of STRING type (without car and cdr,
just message_port_pub(pmt::mp("strobe"), pmt.intern("12345678")); ), then I
need to send from the port Message out a PMT message of STRING type.

But I receive the message in a BLOB type. I was trying all types of
methods, but I can't convert from BLOB to String If I send BLOB it doesn't
work.

The message comes in the cdr of the PMT, so i tried with different versions
of this code

pmt::pmt_t blob(pmt::cdr(msg));
const char *aux = reinterpret_cast(pmt::blob_data(blob));

pmt::pmt_t snrf2 = pmt::intern(std::string(aux));
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Re: [Discuss-gnuradio] Problem processing BLOB type in a new block for IEEE 802-11 transceiver

[Marcus Müller]

Hi Cristian,

a blob is not a string.

You MUST NOT

const char *aux = reinterpret_cast(pmt::blob_data(blob));
pmt::pmt_t snrf2 = pmt::intern(std::string(aux));

ever. Blob data is *not* zero-terminated and it's absolutely legal to
contain the zero byte.

While a std::string might actually contain zero bytes, there's nothing
guaranteeing that for the pmt string type. Also: it doesn't really make
sense to try and convert something that is not a string to a string type.

So, if your Tx App takes arbitrary data, it shouldn't be consuming PMT
strings (which actually come with quite a performance hit, by the way,
if used to transport info), and if it actually only accepts strings,
then you can't just put arbitrary binary data through it.

Best regards,
Marcus

On 06/30/2017 06:13 PM, Cristian Rodríguez wrote:
>
> Hi all.
>
> I'm trying to convert a variable from BLOB to String.
>
> I'm trying to do this.
>
> Imágenes integradas 1
>
> Before, the next block was instead of WiFi App.
>
> Imágenes integradas 2
> Message strobe sends a PMT message of STRING type (without car and
> cdr, just message_port_pub(pmt::mp("strobe"), pmt.intern("12345678"));
> ), then I need to send from the port Message out a PMT message of
> STRING type.
>
> But I receive the message in a BLOB type. I was trying all types of
> methods, but I can't convert from BLOB to String If I send BLOB it
> doesn't work.
>
> The message comes in the cdr of the PMT, so i tried with different
> versions of this code
>
> pmt::pmt_t blob(pmt::cdr(msg));
> const char *aux = reinterpret_cast *>(pmt::blob_data(blob));
>
> pmt::pmt_t snrf2 = pmt::intern(std::string(aux));
> std::cout << "Es blob " < message_port_pub(pmt::mp("message out"), snrf2);
>
> There, i try to convert it to a char and later from char to String,
> but it doesn't work.
>
> What do you think i can do? What i need is to take de data in BLOB
> format, convert it to String, save it in a PMT message and send it.
>
> Thanks a lot for your time to read.
>
> Best regards,
>
> Cristian
>
>
>
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Re: [Discuss-gnuradio] How to receive a finite number of samples at a future time using UHD/GNURadio?

[Marcus Müller]

Hi Eric,

this mail kind of fell through the cracks. Have you found a solution to
this, yet? 

It's not overly clear from the documentation, but the finite_acquisition
method really bypasses parts of what you configure as behaviour for the
USRP_source. So, ok, that won't work.

The second one might be slightly off, syntaxwise. You'll need to create
a stream_cmd_t (of the right type), not use one of the type constant
fields of stream_cmd_t (just as you do in the next approach).

The third might work, but really breaks GNU Radio idea of processing
streams of samples; so, I'm not 100% sure what is appropriate for you :(

Best regards,

Marcus

On 04/24/2017 09:30 PM, Eric Martin wrote:
> I'm using the GNURadio python interface to UHD, and I'm trying to set
> a specific time to start collecting samples and either collect a
> specific number of samples or stop the collection of samples at a
> specific time. Essentially, creating a timed snapshot of samples. This
> is something similar to the C++ Ettus UHD example 'rx_timed_sample'.
>
> I can get a flowgraph to start at a specific time, but I can't seem to
> get it to stop at a specific time (at least without causing
> overflows). I've also tried doing a finite aquisition, which works,
> but I can't get it to start at a specific time. So I'm kind of lost at
> what to do next.
>
> Here is my try at the finite acquisition (seems to just ignore the
> start time and collects 0 samples):
>
> num_samples = 1000
>
> usrp = uhd.usrp_source(
> ",".join(("", "")),
> uhd.stream_args(
> cpu_format="fc32",
> channels=range(1),
> ),
> )
>
> ...
>
> usrp.set_start_time(absolute_start_time)
> samples = usrp.finite_acquisition(num_samples)
>
>
> I've also tried some combinations of following without success
> (TypeError: in method 'usrp_source_sptr_issue_stream_cmd', argument 2
> of type '::uhd::stream_cmd_t const &'):
>
> usrp.set_command_time(absolute_start_time)
> usrp.issue_stream_cmd(uhd.stream_cmd.STREAM_MODE_NUM_SAMPS_AND_DONE)
> I also tried the following in a flowgraph:
>
> ...
> usrp = flowgrah.uhd_usrp_source_0
> absolute_start_time = uhd.uhd_swig.time_spec_t(start_time)
> usrp.set_start_time(absolute_start_time)
>
> flowgrah.start()
>
> stop_cmd = uhd.stream_cmd(uhd.stream_cmd.STREAM_MODE_STOP_CONTINUOUS)
> absolute_stop_time = absolute_start_time +
> uhd.uhd_swig.time_spec_t(collection_time)
>
> usrp.set_command_time(absolute_stop_time)
> usrp.issue_stream_cmd(stop_cmd)
>
> For whatever reason the flowgraph one generated overflows consistently
> for anything greater than a .02s collection time.
>
> I posted this question on stack overflow without any success:
> http://stackoverflow.com/questions/43420300/how-to-receive-a-finite-number-of-samples-at-a-future-time-using-uhd-gnuradio
>
> Any help would be greatly appreciated!!
>
> Thanks.
>
>
>
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Re: [Discuss-gnuradio] dBm and dB Measurements

[GNUBeginner]

 

I have tried to attach a table as a jpg file and hope that it works.



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Re: [Discuss-gnuradio] dBm and dB Measurements

[Marcus Müller]

GNU Beginner,

this is getting stupid. I've told you repeatedly NOT to use Nabble,
because it is a very bad mailing list frontend.

Please subscribe directly to the mailing list under
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio .

Best regards,

Marcus


On 30.06.2017 20:30, GNUBeginner wrote:
>  
>
> I have tried to attach a table as a jpg file and hope that it works.
>
>
>
> --
> View this message in context: 
> http://gnuradio.4.n7.nabble.com/dBm-and-dB-Measurements-tp64413p64430.html
> Sent from the GnuRadio mailing list archive at Nabble.com.
>
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[Discuss-gnuradio] Change value of a Variable defined in the flowgraph from a block

[Cristian Rodríguez]

Hi everyone.

I created a variable in the flowgraph called freq_Tx.

[image: Imágenes integradas 2]

This is assigned as the central freq of the block USRP source and is used
by several blocks to do signal processing.

I need to listen two different frequencies in my application. For example
one minute, 2.4 GHz and other minute 2.5GHz, depending of a specific logic.
How can I, from a block, modify this variable? I mean, something like

set_freq_Tx(new value)

In this moment i'm doing it through a QT GUI RANGE,  but i need to set it
automatically, then I think it must be a variable in the flowgraph, but I
don't know if it can be modified from a block in the flowgraph.

Do you think is it possible?

If yes, may anyone please shares me a reference page or an example.

If not, my other option is to create the variable in my block, send it as
an input to the blocks which use it, and to the USRP as a command. But it
looks longer in time.

Thanks in advance.

Best regards,

Cristian
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Re: [Discuss-gnuradio] Convert recorded FM wav file to I,Q values

[Cinaed Simson]

On 06/28/2017 10:55 PM, Jahnavendra Mattipa wrote:
> Hello all,
>Is there any possibility to convert the recorded FM 'wav' file to I,Q
> values, if possible please tell me how to do this?

Well it depends upon what you mean by 'wav' file.

For a real valued signal with constant amplitude - my guess as to what
you mean, namely

 Acos(wt+phi)

use the trigonometric identity

  cos(wt+phi)=cos(wt)cos(phi)-sin(wt)sin(phi)

- which is easy to derive from complex exponentials.

Then set

  I=Acos(phi)
  Q=Asin(phi)

Hence

  Acos(wt+phi)=Icos(wt)-Qsin(wt)

-- Cinaed

> 
> 
> Best reagards,
> M. Jahnvendra
> 
> 
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