I haven't looked into how the samples come from the USRP to the PC. Perhaps the usrp2 source block will tell more?
On Wed, Aug 26, 2009 at 4:23 AM, Ulrika Uppman <[email protected]> wrote: > Thank you very much for your explenation Colby! I now understand how the > message queue is used in the rx code. > > However, I would still like to know more about how the data is transported > between for example the usrp block and the next block (in the 802.11b rx > case this would be the resampling block). If I understand it right, the usrp > sends frames of data including a header, timestamp and a number of data > samples. When connecting the blocks in the python code, where does the > transformation from frames into a stream happen? I've tried to read the code > and documentation about the connection and starting of flow graphs, but I > could still use some hints... > > Tnx, > /Ulrika > > ________________________________ > > Från: Colby Boyer [mailto:[email protected]] > Skickat: den 26 augusti 2009 05:09 > Till: Ulrika Uppman > Kopia: GNU Radio Discussion > Ämne: Re: [Discuss-gnuradio] fundamentals of block-connections, message > queue etc. > > > Within the BBN RX side, all the processing blocks are stuck together so > that data "streams" from each block to the next. In the final block, when a > packet is successfully decoded it is loaded in a message queue. The loading > into the message queue is done within the C++ code, not the python. > > There is another thread running that will sleep on an empty queue and will > not wake up until something is inserted into the queue. When a message > enters the queue, the thread wakes up, takes out the message and then prints > it out via a call back function. > > Check the source code for the message queue to see if there is another > function to add a message. > > Thanks, > Colby > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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