Dear Team GNURadio, Please get back to us. We are facing the same problem rite now as well.
Best Regards, Huzaifa huzaifazafar108 wrote: > > Sir, > > Repeat is set to yes. I guess this is not the problem. Also, without the > USRP block (by sending the modulation output to the demoudalation input), > everything is working the way it should. > > Best, > Huzaifa > > > > Ben Reynwar wrote: >> >> For the vector source it looks like you're using [1,1,1,0,0,0]. >> Perhaps the rest is getting cut-off, but if not then I would change >> this to use a long random vector for the testing. If you are using >> [1,1,1,0,0,0] repeated then the four symbols won't be used with >> similar frequency, which might make things more difficult. >> >> Also the differential encoding and decoding should be taken care of >> within the DPSK mod and demod blocks, so that should be OK. >> >> On Sun, Apr 8, 2012 at 2:25 PM, huzaifazafar108 >> <[email protected]> wrote: >>> >>> We just removed the throttle blocks and the same problem remains. Please >>> let >>> us know how to achieve symbol synchronization. >>> >>> >>> >>> 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 >>>>>> [email protected] >>>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> >>>>> >>>>> _______________________________________________ >>>>> Discuss-gnuradio mailing list >>>>> [email protected] >>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> >>>>> >>>> >>> >>> -- >>> View this message in context: >>> http://old.nabble.com/Problem-with-USRP%21-tp33653047p33653150.html >>> Sent from the GnuRadio mailing list archive at Nabble.com. >>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> [email protected] >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > > -- View this message in context: http://old.nabble.com/Problem-with-USRP%21-tp33653047p33660591.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
