Signal Processing Blocks in GRC

Hi all,

I recently started to use Gnu Radio and I want to implement new signal
processing blocks in GRC so others could easily use them in a graphical
environment. Most common blocks are already available, however, some are

Python is new to me, but I’m making progress. I understand the structure
of the example ‘howto-square-ff’ (at least I think so) and I know what
changes to make for my own blocks.

make install

don’t produce any errors.

The xml file for embedding into GRC seems to be quite easy. However,
when running the example in GRC I get the message:

NameError: global name ‘howto’ is not defined

On the other hand, if I change the example to have the package name ‘gr’
instead of ‘howto’ (I’ve changed the source code as well, my function is
called sub4_ff()), I get another message:

module’ object has no attribute ‘sub4_ff’

Here is my howto_square_ff.xml:

<?xml version="1.0"?> Square howto_square_ff Test from gnuradio import gr howto.test_square_ff() in float out float

Please help me with this, I already tried a lot!

I am using:

  • openSUSE 11.1 (64bit)
  • Gnu Radio 3.2.2
  • howto example 3.2