On Fri, Apr 4, 2008 at 12:51 AM, Darryl Ross <
address@hidden> wrote:
(Apologies is this is a duplicate, I think I sent the first one before my subscription activated)
Hi All,
I'm having a problem trying to use the flex_demod() method of
gnuradio.pager:
address@hidden bin]# ./alsa_flex.py
gr_fir_fff: using SSE
Traceback (most recent call last):
File "./alsa_flex.py", line 22, in ?
tb = top_block(queue)
File "./alsa_flex.py", line 17, in __init__
self.connect(src, dst)
File "/opt/gnuradio/lib/python2.4/site-packages/gnuradio/gr/top_block.py", line 70, in connect
self._connect(points[i-1], points[i])
File "/opt/gnuradio/lib/python2.4/site-packages/gnuradio/gr/top_block.py", line 76, in _connect
dst_block.basic_block(), dst_port)
File "/opt/gnuradio/lib/python2.4/site-packages/gnuradio/gr/gnuradio_swig_py_runtime.py", line 1493, in connect
return _gnuradio_swig_py_runtime.gr_top_block_sptr_connect(*args)
ValueError: itemsize mismatch: audio_alsa_source(1):0 using 4, flex_demod(2):0 using 8
Reading through some of the documentation, it looks to me like the
itemsize variable is the size of the samples?
yes audio_source is giving you floats
flex_demod is looking for gr_complex
I'm guessing that I need to process (resample?) the signal from the
sound card before passing it to the flex decoder, but I'm not sure what
that processing would be. I'm very new to signal processing, so don't
know what search terms I should be using.
Can anyone give me a pointer?
I think flex_demod is looking for complex data at baseband
My (very simple) program so far is:
#!/usr/bin/python
from gnuradio import audio, gr, pager
sample_rate = 48000
audio_device = 'hw:0'
class top_block(gr.top_block):
def __init__(self, queue):
gr.top_block.__init__(self)
src = "" audio_device)
dst = pager.flex_demod(queue)
self.connect(src, dst)
if __name__ == '__main__':
queue = gr.msg_queue()
tb = top_block(queue)
tb.start()
while True:
if not queue.empty_p():
msg = queue.delete_head()
print msg.to_string()
Thanks
-Darryl
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