Dear John, Waiting for your response...
And the reason for using TX/RX is that we connected the antennas on TX/RX ports on the daughtercard (in both transmitter and receiver). Thanks, Huzaifa John Malsbury wrote: > > A few more things: > > 1) You have both the receive and transmit portions assigned to TX/RX. > This only works if you run in half-duplex mode and stop streaming to the > USRP. This is not the case. > 2) Note the difference between sample rate, symbol rate, and bit rate. > > symbol_rate = sample_rate / samples_per_symbol > bit_rate = sample_rate/bits_per_symbol > > I think there are issues with packing/unpacking of bits. The > requirements for packing and unpacking aren't completely consistent > across the mod/demods within GNU Radio. Let me experiment real quick > and get back to you. > > -John > > > On 04/08/2012 02:34 PM, huzaifazafar108 wrote: >> Dear Marcus, >> >> I truly appreciate your prompt reply. However, I am not sure what should >> I >> put in the 'modulus' field of the block. By hit and trial, wrong outputs >> are >> emerging. Please guide. >> >> Best Regards, >> Huzaifa >> >> >> >> Marcus D. Leech wrote: >>>> We just removed the throttle blocks and the same problem remains. >>>> Please >>>> let >>>> us know how to achieve symbol synchronization. >>>> >>>> >>> Well, you're using DPSK, but not using a differential encoder on the TX >>> side, nor a differential decoder on the RX side. >>> >>>> huzaifazafar108 wrote: >>>>> Dear John, >>>>> >>>>> Thank you for such a prompt reply. Okay, we will remove the throttle >>>>> blocks just now. But can you guide us how to achieve symbol >>>>> synchronization then? >>>>> >>>>> Best Regards, >>>>> Huzaifa >>>>> >>>>> >>>>> >>>>> John Malsbury wrote: >>>>>> You do not need to use throttles when using a UHD sink/source, >>>>>> because >>>>>> the device provides timing for the flowgraph. >>>>>> >>>>>> Remove the throttles and try again. If you still see the failure I'd >>>>>> say you are not achieving symbol sync. >>>>>> >>>>>> -John >>>>>> >>>>>> >>>>>> >>>>>> On 04/08/2012 01:58 PM, Huzaifa Zafar wrote: >>>>>>> Dear all, >>>>>>> >>>>>>> I am working with 3 people on a project involving GNU Radio and >>>>>>> USRP1. >>>>>>> We have tried to implement a simple point to point digital >>>>>>> communication system in GRC involving DQPSK modulation. Using a >>>>>>> vector >>>>>>> source we are sending a finite stream of zeros and ones (the vector >>>>>>> source has Repeat set to yes). On the receiver side, what we receive >>>>>>> is really very strange: The same stream of zeros and ones, but with >>>>>>> extra zeros in between our actual data. For example, we send three >>>>>>> ones and three zeros, but what we receive is a one followed by seven >>>>>>> zeros, another one followed by seven zeros, another one followed by >>>>>>> seven zeros, and then a zero followed by seven zeros e.t.c. We tried >>>>>>> to experiment more by using the 'KEEP 1 in N' block and the >>>>>>> 'DECIMATING FIR FILTER', but things are not working out the way they >>>>>>> should. >>>>>>> >>>>>>> I am also attaching a snapshot of the .grc file for your reference. >>>>>>> Please tell us the reason why these extra zeros are present between >>>>>>> our data bits, and the way to combat this effect (remember that the >>>>>>> decimating fir filter and keep 1 in N block are not showing the >>>>>>> desired output). Any kind of help is appreciated in advance. >>>>>>> >>>>>>> -- >>>>>>> Huzaifa Zafar >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> 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 >>>>>> >>>>>> >>> >>> -- >>> Marcus Leech >>> Principal Investigator >>> Shirleys Bay Radio Astronomy Consortium >>> http://www.sbrac.org >>> >>> >>> >>> _______________________________________________ >>> 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 > > -- View this message in context: http://old.nabble.com/Problem-with-USRP%21-tp33653047p33653209.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
