Guided Tutorials - Experience

GNU Radio
1

Hello,

I did 2 of the Guided Tutorials - Programming GNU Radio in Python and
C++ and want to tell you about my experiences.

First thanks for making this tutorials! They really help me to get a
good start with GNU Radio.

Tutorial with Python: Since I don t have any programming experience in
Pyton (and C++) I really liked it that it is very detailed! Could do it
and understand everything!

Tutorial with C++: Really had problems doing this tutorial. I must admit
that my C++ knowledge is very low.

  • In the tutorial there is just written to edit the and how to edit the
    .cc file. But in the header there are also things to be edited.
  • After declaring the function get_minimum_distances in header file and
    trying to compile (make) I get the error: unknown variable d_gray_code.
    So I guess in the .cc file there has to be done some assignment like
    d_gray_code = gray_code ?
  • After doing some editings in header and .cc file I managed to compile.
  • To prevent any errors I copied the given (on the tutorial page) .xml
    code into my .xml file. After cmake …/ → make → sudo make install
    → sudo ldconfig → restart GRC → new block did not appear ?
  • Maybe it s because the last 6 lines of xml file ? There appear
    2 times. After editing the file made by gr_modtool with the
    instructions it worked :slight_smile:

But after having done a QA test as it is written on the tutorial I get
wrong results (AssertError). Seems that although I call

qpsk = tutorial.my_qpsk_demod_cb(gray_code) with gray_code = false
The code just enters the if clause with gray_code == true?

Do you have any idea why? Here are my files, which are nearly the same
as the ones in examples.
https://dl.dropboxusercontent.com/u/33858807/my_qpsk_demod_cb_impl.cc

https://dl.dropboxusercontent.com/u/33858807/my_qpsk_demod_cb_impl.h
https://dl.dropboxusercontent.com/u/33858807/qa_my_qpsk_demod_cb.py

Thank you in advance!

Best regards,
Vlad

2

Vlad,

thanks for going through the guided tutorials, and thanks for your
feedback. We’ll address those soon and fix the tutorials.

As for your solution, I’m not sure. I recommend putting a couple of
print statements so you can tell what’s going on.

cheers,
M

3

On 20.10.2014 13:37, Martin B. wrote:

Hello Martin,

thank you for the hint! After printing the variable, I noticed I
assigned a variable wrongly.

However, now everything works fine :slight_smile:

If there is someone else who has problems doing this tutorial, here is
the code :

https://dl.dropboxusercontent.com/u/33858807/GNURadio/my_qpsk_demod_2_cb_impl.cc

https://dl.dropboxusercontent.com/u/33858807/GNURadio/my_qpsk_demod_2_cb_impl.h

https://dl.dropboxusercontent.com/u/33858807/GNURadio/qa_my_qpsk_demod_2_cb.py

https://dl.dropboxusercontent.com/u/33858807/GNURadio/tutorial_my_qpsk_demod_2_cb.xml

Best regards,
Vlad

4

On 10/22/2014 11:26 AM, Vlad Stoica wrote:

thank you for the hint! After printing the variable, I noticed I
assigned a variable wrongly.

However, now everything works fine :slight_smile:

If there is someone else who has problems doing this tutorial, here is
the code :

I would like to point out that we do provide the ‘solutions’ in a
dedicated repo:

Cheers,
M

5

I would like to point out that we do provide the ‘solutions’ in a
dedicated repo:

GitHub - gnuradio/gr-tutorial: A tutorial OOT module for GNU Radio

Cheers,
M

Oops, sorry! I somehow missed that…