Re: [Discuss-gnuradio] Error while receiving

[kaleem ahmad]

Addition to my above question I also want to know how can I connect two
different flowgraphs with 'usrp.source_c', 

I was trying following

src = usrp.source_c(...)
fg.connect((src, 0),.......blocks of fg1)
fg.connect((src, 1),.......blocks of fg2)

But it is not working I got following error

"Traceback (most recent call last):
  File "./usrp_Master.py", line 309, in <module>
    fg = my_graph()
  File "./usrp_Master.py", line 87, in __init__
    self.rxpath = receive_path(options, times)
  File "/usrp/cognitive/gr-comac1.0/src/python/receive_path.py", line 227,
in __init__
    self.connect((self.u,1), self.s2v)
  File "/usr/local/lib/python2.5/site-packages/gnuradio/gr/hier_block2.py",
line 50, in connect
    self._connect(points[i-1], points[i])
  File "/usr/local/lib/python2.5/site-packages/gnuradio/gr/hier_block2.py",
line 56, in _connect
    dst_block.basic_block(), dst_port)
  File
"/usr/local/lib/python2.5/site-packages/gnuradio/gr/gnuradio_swig_py_runtime.py",
line 946, in connect
    return _gnuradio_swig_py_runtime.gr_hier_block2_sptr_connect(*args)
ValueError: port number 1 exceeds max of 0
"

Actually with one flowgraph I want to sense the spectrum and with the other
flowgraph I want to receive normal data. My idea is that when I want to
sence the spectrum I can change some parameters of usrp.source_c and start
processing sink of one flow graph and when I want to receive normal data I
can again change some parameters of usrp.source_c and can process the sink
of corresponding flowgraph. BUT FOR THIS BOTH FLOWGRAPHS SHOULD BE CONNECTED
TO usrp.source_c AS WE CAN HAVE ONLY ONE usrp.source_c OPEN AT A TIME????

Is above idea correct and how can I construct such graph????

Best Regards
Kaleem Ahmad



kaleem ahmad wrote:
> 
> Thanks Eric,
> 
> Can you give me a bit more explanation about why it is 'doomed to fail and
> will sooner or later exhaust all memory'. Actually my plan is to run this
> graph for ever and I dont have any idea why a graph(especially this one) 
> will exhibit such behavior and what measure can be taken to avoid
> this....?
> 
> Any clue will be great help for me.
> 
> Best Regards
> Kaleem Ahmad
> 
> 
> 
> Eric Blossom wrote:
>> 
>> On Thu, Oct 09, 2008 at 07:29:51AM -0700, kaleem ahmad wrote:
>>> 
>>> Hi,
>>> 
>>> I am using USRP+RFX1400+SUSI
>>> 
>>> I am using following flow graph to receive data>
>>> 
>>> usrp_source_c -> gr.fir_filter_ccf -> gr.quadrature_demod_cf ->
>>> gr.simple_correlator -> gr.vector_sink_b
>>> 
>>> Some time I receive following error:
>>> 
>>> *** glibc detected *** python: free(): invalid next size (fast):
>>> 0x08fcd970
>>> ***
>>> Segmentation fault
>>> 
>>> Can you suggest what can be the problem and what can I do to solve it.
>>> 
>>> Thanks
>>> Kaleem Ahmad
>> 
>> Not sure where it's actually blowing up (definitely a bug somewhere).
>> A stack trace from gdb would provide clues.
>> 
>> However, the flow graph you give above is doomed to fail.  It will
>> sooner or later exhaust all memory on your system.  When this happens
>> is should fail gracefully, but it may not.
>> 
>> Eric
>> 
>> 
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden
>> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>> 
>> 
> 
> 

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