Re: Generator error flow graph

[Christophe Seguinot]

Looking more deeply into this, I figure out that this flowgraph must not be used with conventionnal FM Signal

• there is in /gnuradio/gr-analog/examples/ an FM emitter fm_tx.grc
• use this to generate dummy.dat ( (*)rename the file at your convenience to put it in the current folder for example)
  
• then run the fm_rx.grc, rename the file source according to your dummy.dat location, (the DC blocker to the audio_sink input is not neeeded here.
  
• and it works !

(*) by default, GNURadio Read/write files to the folder from which GNURadio-companion was launched. This is the home directory if your run .grc file by double clicking them.

Regards, Christophe

On 18/03/2021 11:02, Christophe Seguinot wrote:

Hi Frédérique

About dummy.dat . The dummy.dat file (see file source in tyour flowgraph) is a binary file which is not present in the example folder containing a list of complex samples. You have to find some recorded FM Signal to run the flowgraph.

Gnuradio can write (using file Sink) and read (using file source) such files which are generally given .bin or .dat extension. This allows to run GNURadio whitout hardware.

About this fm_rx.grc flowgraph  available in gnuradio/gr-analog/examples/fm_rx.grc.

This flowgraph is quite outdated may be we should update this !

I was not able to run it successfully. (analog examples which where part of older GNURadio version can generally be improved using more recent GNURadio blocks)

It requires at least a DC blocker before the audio_sink to reject DC component.

I personnally use a quite different flowgraph for FM demodulation

If you're interested, I've got a complete running example including .bin files used in my classes, however it's written in French (just send me a private mail)

Regards, Christophe

On 18/03/2021 09:58, COURANT Frederique - Contractor wrote:

Hi Cinaed,

 

Sorry but I am beginner in USRP. What is the file dummy.dat please ?

I don’t have front end hardware.

 

If I run fmtest.py I have no problem but my target is to generate my own python code with my flow graph.

 

Thanks you very much for your help.

 

Fred

 

De : Cinaed Simson <cinaed.simson@gmail.com>
Envoyé : mercredi 17 mars 2021 20:45
À : COURANT Frederique - Contractor <frederique.courant@external.thalesgroup.com>
Cc : discuss-gnuradio@gnu.org
Objet : Re: Generator error flow graph

 

That file will generate any error unless you have the input file "dummy.dat".

Try

   grep dummy.dat ./fm_rx.grc

which will return

   file: dummy.dat

or just open the file with GRC and replace file source with your front end hardware.

But you can run

  gnuradio/share/gnuradio/examples/analog/fmtest.py

without using the GRC.

-- CInaed

P.S. - please keep the discussion on the mailing list. Thank you.

On 3/17/21 4:37 AM, COURANT Frederique - Contractor wrote:

Hi Cinaed,

 

Sorry but I can’t attach my flow grap.

But for example, I have this error with fm_rx.grc available in gnuradio/gr-analog/examples.

 

Thanks for your help.

 

Fred

 

De : Discuss-gnuradio <discuss-gnuradio-bounces+frederique.courant=external.thalesgroup.com@gnu.org>De la part de Cinaed Simson
Envoyé : mercredi 17 mars 2021 09:18
À : discuss-gnuradio@gnu.org
Objet : Re: Generator error flow graph

 

HI Fred - how about at least 1 example GRC which demonstrates the problem?

The  GRC file is a text file which you can attach to email.

-- Cingnuradio/share/gnuradio/examples/analog/aed

On 3/17/21 12:12 AM, COURANT Frederique - Contractor wrote:

Hello all,

 

I would like to known if someone has ever had this error when you want to generate python code with gnuradio :

Generate Error: ‘catch_execptions’

>>>Failure

Traceback (most recent call last):

File “/usr/local/lib/python3/dist-packages/gnuradio/grc/gui/Application.py”, line 710, in _handle_action

generator.write()

File “/usr/local/lib/python3/dist-packages/gnuradio/grc/core/generator/top_block.py”, line 83, in write

for filename, data in self._build_python_code_from_template():

File “/usr/local/lib/python3/dist-packages/gnuradio/grc/core/generator/top_block.py” line 123, in _build_python_code_from_template

‘catch_excetions’:fg.get_option(‘catch_exceptions’)

File “/usr/local/lib/python3/dist-packages/gnuradio/grc/core/FlowGraph.py”, line 181, in get_option

              Return self.options_block.params[key].get_evaluated()

KeyError: ‘catch_exceptions’

 

The problem is present with my personal flow graph and examples available with gnuradio.

I’m using UHD 4.0 and gnuradio 3.8.

 

Thanks for your help.

 

Best regards.

 

Fred