The burst shaper actually has a manual page: https://gnuradio.org/doc/doxygen/classgr_1_1digital_1_1burst__shaper__cc.html
The resampler will give you some rolloff, so you have a more usable digital signal going to the USRP. Check out uhd_packet_?x for details on how the USRP is configured. Its sampling rate is the rate at which it'll consume data from the resampler. -- M On 08/17/2017 09:31 AM, Rui ZOU wrote: > Hi, > > I'm studying the example packet_tx and uhd_packet_tx in > /usr/local/share/gnuradio/examples/digital/packet. I have some questions > regarding the process of packet transmission and the flow graph. > > Why burst shaper block is needed? How do its parameters affect tx/rx? > > Why polyphase arbitrary resampler block is needed? How do its parameters > affect tx/rx? > > Packets are generated at the host at fixed intervals with variable > length in a range. What parameters are passed to the USRP to control the > actual rate of transmission? Or this is not controlled explicitly by the > flowgraph, so the USRP just transmits at whatever rate it sees suitable. > Is it the sample rate of USRP sink? > > From the flow graph, the process to generate baseband symbols is clear. > How the modulating pulse is generated and how it is multiplied with the > baseband symbols are not clear to me. Is it achieved by the polyphase > arbitrary resampler block? In digital communication textbooks, the > baseband modulating pulse is a continuous waveform. If generated in > digital system, like using GNU Radio in a computer, how to do it then? > > Regards, > > Rui > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
