Block for continuous production of samples

Good morning,
I need to implement a double 802.15.4-802.11b transmitter that transmits
packets in asynchronous (or aperiodical) mode.
I realized a simple program where the output of the two trasmitters are
added together to generate the output stream.
Unfortunately, when one of the two transmitters ends to generate a
packet, also the other one stops. It happens ( i think! ) because there
are no samples for the adder to combine with and the forecast() method
stops the execution.
By the way, I found online a similar discussion:
http://www.mail-archive.com/[email protected]/msg08387.html
In order to have a countinuos output stream even when the two
transmitters are inactive, could I implement a gnuradio c++ block with
the following characteristics?
-performs a continuous production of null samples (when there are no
input to the block)
-lets the samples unchanged if there are samples at his input.

Thanks a lot,
Bertussi Daniele - University of Brescia, Italy

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Citando Daniele B. [email protected]:

Thanks a lot,
Bertussi Daniele - University of Brescia, Italy

Good morning, does anyone have an idea?
Thanks a lot,
Bertussi Daniele - University of Brescia, Italy

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On Thu, Feb 25, 2010 at 04:16:20PM +0100, Daniele B. wrote:

Good morning,
I need to implement a double 802.15.4-802.11b transmitter that transmits packets in asynchronous (or aperiodical) mode.
I realized a simple program where the output of the two trasmitters are added together to generate the output stream.
Unfortunately, when one of the two transmitters ends to generate a packet, also the other one stops. It happens ( i think! ) because there are no samples for the adder to combine with and the forecast() method stops the execution.
By the way, I found online a similar discussion:
http://www.mail-archive.com/[email protected]/msg08387.html
In order to have a countinuos output stream even when the two transmitters are inactive, could I implement a gnuradio c++ block with the following characteristics?
-performs a continuous production of null samples (when there are no input to the block)
-lets the samples unchanged if there are samples at his input.

I wrote some code a while ago that attempted exactly that (I’ll email
you the
stuff off-list), but you need to be careful that it does exactly what
you want. At the very least, put in a throttle or you’ll end up creating
billions of zeros before the scheduler comes round to insert your
signal.

MB


Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin B.
Research Associate

Kaiserstraße 12
Building 05.01
76131 Karlsruhe

Phone: +49 721 608-3790
Fax: +49 721 608-6071
www.cel.kit.edu

KIT – University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association

Citando Martin B. [email protected]:

Goodmorning,
thanks a lot for your help! It’s exactly what i want.
But during installation “make check” give this:

Making check in config
make[1]: Entering directory /home/sdr3/gritloop/config' make[1]: Nothing to be done forcheck’.
make[1]: Leaving directory /home/sdr3/gritloop/config' Making check in src make[1]: Entering directory/home/sdr3/gritloop/src’
Making check in lib
make[2]: Entering directory /home/sdr3/gritloop/src/lib' make check-am make[3]: Entering directory/home/sdr3/gritloop/src/lib’
make[3]: Nothing to be done for check-am'. make[3]: Leaving directory/home/sdr3/gritloop/src/lib’
make[2]: Leaving directory /home/sdr3/gritloop/src/lib' Making check in python make[2]: Entering directory/home/sdr3/gritloop/src/python’
make check-TESTS
make[3]: Entering directory `/home/sdr3/gritloop/src/python’
Exception RuntimeError: ‘maximum recursion depth exceeded in
subclasscheck’ in <type ‘exceptions.AttributeError’> ignored
Traceback (most recent call last):
File “./qa_burst2stream.py”, line 23, in
import gritloop
File “/home/sdr3/gritloop/src/lib/gritloop.py”, line 6, in
import _gritloop
ImportError: /home/sdr3/gritloop/src/lib/.libs/_gritloop.so: undefined
symbol: _ZTIN5boost21thread_resource_errorE
Exception RuntimeError: ‘maximum recursion depth exceeded in
subclasscheck’ in <type ‘exceptions.AttributeError’> ignored
Traceback (most recent call last):
File “./qa_channels.py”, line 25, in
import gritloop, gritloopchans
File “/home/sdr3/gritloop/src/lib/gritloop.py”, line 6, in
import _gritloop
ImportError: /home/sdr3/gritloop/src/lib/.libs/_gritloop.so: undefined
symbol: _ZTIN5boost21thread_resource_errorE
./run_tests: line 39: ./qa_flow_sync.py: Permission denied
FAIL: run_tests

1 of 1 tests failed

make[3]: *** [check-TESTS] Error 1
make[3]: Leaving directory /home/sdr3/gritloop/src/python' make[2]: *** [check-am] Error 2 make[2]: Leaving directory/home/sdr3/gritloop/src/python’
make[1]: *** [check-recursive] Error 1
make[1]: Leaving directory `/home/sdr3/gritloop/src’
make: *** [check-recursive] Error 1

And after “sudo make install” I have tried a script with the following
row
“from gnuradio import gritloop”
but return an error and doesn’t find your libraries ( libraries are
installed in the right Python path).
What can i do?
Thanks a lot,
Bertussi Daniele- University of Brescia

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