# Ofdm mod error **URL:** \ **Category:** GNU Radio\ **Created:** [August 18, 2015, 7:39am UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047 "2015-08-18T07:39:08Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Sadaf\_N](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@Sadaf\_N](https://www.ruby-forum.com/u/Sadaf_N)\ **Post date:** [August 18, 2015, 7:39am UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/1 "2015-08-18T07:39:08Z")
Hi! I’m using gnuradio on ZedBoard and was trying a simple OFDM Mod system just like in this video [![](https://img.youtube.com/vi/LZDWfnrxo6c/maxresdefault.jpg "GNURADIO : Quick OFDM") ](https://www.youtube.com/watch?v=LZDWfnrxo6c) the flowgraph just looks like this… random source\>short to float\>ofdm mod\>throttle\>wx gui fft sink and this comes up… "Generating: “/home/analog/Documents/top\_block.py” Executing: “/home/analog/Documents/top\_block.py” Fontconfig warning: ignoring C.UTF-8: not a valid language tag Using Volk machine: neon\_hardfp Traceback (most recent call last): File “/home/analog/Documents/top\_block.py”, line 101, in tb = top\_block() File “/home/analog/Documents/top\_block.py”, line 62, in **init** verbose=None, File “/usr/lib/python2.7/dist-packages/gnuradio/digital/ofdm.py”, line 95, in **init** constel = psk.psk\_constellation(arity) File “/usr/lib/python2.7/dist-packages/gnuradio/digital/psk.py”, line 77, in psk\_constellation constellation = digital\_swig.constellation\_psk(points, pre\_diff\_code, m) AttributeError: ‘module’ object has no attribute ‘constellation\_psk’ > > > Done" I have no idea what to do next… THANKS! 🙂 ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 18, 2015, 6:21pm UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/2 "2015-08-18T18:21:07Z")
Patrcia, try the new OFDM blocks. I suggest starting with the example ofdm\_loopback.grc and working from there to see how things work, Cheers, Martin ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 20, 2015, 8:43am UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/3 "2015-08-20T08:43:34Z")
Hi! I think I’m using the latest OFDM blocks. I then tried using the ofdm\_loopback.grc and an error occured that is similar to the first one… "Showing: “/home/analog/Documents/ofdm\_loopback.grc” Generating: “/home/analog/Documents/ofdm\_loopback\_example.py” Executing: “/home/analog/Documents/ofdm\_loopback\_example.py” Fontconfig warning: ignoring C.UTF-8: not a valid language tag Using Volk machine: neon\_hardfp Traceback (most recent call last): File “/home/analog/Documents/ofdm\_loopback\_example.py”, line 290, in tb = ofdm\_loopback\_example() File “/home/analog/Documents/ofdm\_loopback\_example.py”, line 186, in **init** scramble\_bits=False File “/usr/lib/python2.7/dist-packages/gnuradio/digital/ofdm\_txrx.py”, line 187, in **init** crc = digital.crc32\_bb(False, self.packet\_length\_tag\_key) AttributeError: ‘module’ object has no attribute ‘crc32\_bb’ > > > Done" ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 20, 2015, 10:53am UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/4 "2015-08-20T10:53:21Z")
i’ve noticed that the digital\_swig causes some error for both… looking at it, there is nothing inside the digital\_swig.py file… is that ok? ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 21, 2015, 7:08pm UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/5 "2015-08-21T19:08:36Z")
Patrcia, this looks more like you don’t have GNU Radio properly installed – these examples will work fine with a full installation of GNU Radio. Cheers, Martin ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 24, 2015, 7:44am UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/6 "2015-08-24T07:44:30Z")
I’m using ZedBoard by ADI as my dev board and this is their instructions for installing everything… [http://wiki.analog.com/resources/tools-software/linux-software/zynq\_images](http://wiki.analog.com/resources/tools-software/linux-software/zynq_images) I did everything in here… It seems everything about the OFDM blocks have similar problem… ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 24, 2015, 6:18pm UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/7 "2015-08-24T18:18:24Z")
The point is that what you’re seeing is clearly a Python telling you that it can’t find the crc32\_bb module nor the constellation\_psk object where they should be, on a proper installation of GNU Radio. This is not a problem of these examples, but of your installation; as Martin hinted, we need to solve that first. Best regards, Marcus ---
**Author:** ![patricia016](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/8dc957/32.png) [@patricia016](https://www.ruby-forum.com/u/patricia016)\ **Post date:** [August 24, 2015, 6:33pm UTC](https://www.ruby-forum.com/t/ofdm-mod-error/243047/8 "2015-08-24T18:33:35Z")
Marcus, I just saw i was still running a 32 bit installation of linux. I just removed my old installation and busy reinstalling a fresh Ubuntu 14.04 LTS. What instalation way is best? Installing by the sudo apt-get install command or just build my own version? best regards, Nick ----- Oorspronkelijk bericht ----- Van: “Marcus Müller” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Aan: [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Verzonden: Maandag 24 augustus 2015 16:59:13 Onderwerp: Re: [Discuss-gnuradio] ofdm mod error The point is that what you’re seeing is clearly a Python telling you that it can’t find the crc32\_bb module nor the constellation\_psk object where they should be, on a proper installation of GNU Radio. This is not a problem of these examples, but of your installation; as Martin hinted, we need to solve that first. Best regards, Marcus On 08/24/2015 07:44 AM, Patrcia Wonder wrote: > I’m using ZedBoard by ADI as my dev board and this is their instructions > for installing everything… > > [Analog Devices Kuiper Linux [Analog Devices Wiki]](http://wiki.analog.com/resources/tools-software/linux-software/zynq_images) > > I did everything in here… > > It seems everything about the OFDM blocks have similar problem… * * * Discuss-gnuradio mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > **[Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)**