# Problem running FCD demo

**URL:** <https://www.ruby-forum.com/t/problem-running-fcd-demo/239902>\
**Category:** GNU Radio\
**Created:** [March 19, 2014, 3:58am UTC](https://www.ruby-forum.com/t/problem-running-fcd-demo/239902 "2014-03-19T03:58:45Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [March 19, 2014, 3:58am UTC](https://www.ruby-forum.com/t/problem-running-fcd-demo/239902/1 "2014-03-19T03:58:45Z")

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I am trying to run the FCD nfm demo with the proplus module. This is  
using  
3.7.3. Everything compiled and loaded fine. I am very tired and going to  
bed.

I would really appreciate someone looking at this. Thanks in advance.

Executing: “/home/mike/fcd\_nfm\_rx.py”

Using Volk machine: avx\_64\_mmx\_orc  
Funcube Dongle Pro+ found as: plughw:1,0  
Dongle sucessfully initialized  
Result of Action :+++++  
FCDAPP 20.03  
Lna gain enabled  
Mixer gain disabled  
If gain set to: 0  
Set Frequency to: 1.62475e+08 Hz, corrected to: 162475008 Hz  
len(audio\_taps) = 463  
audio\_alsa\_source[plughw:1,0]: snd\_pcm\_hw\_params failed: Input/output  
error  
Traceback (most recent call last):  
File “/home/mike/fcd\_nfm\_rx.py”, line 405, in   
tb.Start(True)  
File  
“/usr/local/lib/python2.7/dist-packages/grc\_gnuradio/wxgui/top\_block\_gui.py”,  
line 73, in Start  
self.start()  
File  
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/top\_block.py”,  
line 104, in start  
top\_block\_start\_unlocked(self.\_tb, max\_noutput\_items)  
File  
“/usr/local/lib/python2.7/dist-packages/gnuradio/gr/runtime\_swig.py”,  
line  
4629, in top\_block\_start\_unlocked  
return \_runtime\_swig.top\_block\_start\_unlocked(\*args, \*\*kwargs)  
RuntimeError: check topology failed on audio\_alsa\_source(12) using  
ninputs=0, noutputs=2

---

<div class="post-metadata">

**Author:** ![ghoti143](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/90db22/32.png) [@ghoti143](https://www.ruby-forum.com/u/ghoti143)\
**Post date:** [March 19, 2014, 7:02am UTC](https://www.ruby-forum.com/t/problem-running-fcd-demo/239902/2 "2014-03-19T07:02:42Z")

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Have a look at your dmesg log. You probably see a " not enough  
bandwidth" message. Are you using an usb 2 or an usb 3 port ?

– Volker

Am 19.03.2014 03:57, schrieb Mike H.: