Hi Marcus, Thanks for the advice. I will try it out and see if it will provide the signal that I need.
Regards, Wen Bin On Jan 7, 2015 10:33 PM, "Marcus Müller" <[email protected]> wrote: > Hello Wen Bin, > > for me, "upper side band" modulation implies the following, assuming we're > already in complex baseband, with the middle between USB and LSB shifted to > 0 Hz: (imagine this is a frequency axis): > > <---- -f_sample/2 --- LSB --- f_center==0Hz --- USB --- +f_sample/2 ----> > > If I understand you correctly, you only want to see positive frequencies; > Weaver's method (or its inverse) would simply shift USB by -f_sample/4 and > apply a low pass filter or f_sample/4 passband. If the filtering was done > perfectly, then the newly generated complex baseband signal will contain > exactly the information originally in your USB. If that suits your needs > completely depends on what you actually are transmitting in your USB and > what you want to do with it. So: No one can tell you whether there's a > better method other than you ;) because you know what you need. > > Regarding efficiency: Doing the frequency shift, the low pass filtering > and a decimation can be done at once using the xlating FIR filter block. > Try it, you'll like it; it's heavily optimized. > > Greetings, > Marcus > > On 01/07/2015 07:48 AM, Wenbin Toh wrote: > > Hi Martin, > > Sorry for the late reply. After reading on throttle usage and removing the > throttle, it did solve the audio underrun issue. Thanks you. > > However, I would also like to know if there are any other better and > efficient USB demodulation method. > > Regards, > Wen Bin > On Jan 6, 2015 4:09 PM, "Martin Braun" <[email protected]> wrote: > >> Hi, >> >> I sent you a response just yesterday on the usrp-users mailing list >> suggesting you remove the throttle. Did you try that, and did it not help? >> >> M >> >> On 01/06/2015 08:02 AM, Wenbin Toh wrote: >> > Hi everyone, I have a question regarding the USB demodulation which I >> > have conducted on a sample wav file which I have recorded. I would like >> > to know if there are any solutions to eliminate the audio underrun issue >> > which is shown in attachment "test1". >> > >> > I would also like to ask if there are any other better USB demodulation >> > method other than weaver's method. Would be great if there is any >> > feedback for the USB demodulation which I have done as I feel that there >> > are something wrong with it which I could not pin-point out. >> > >> > PS: I am using ettus X310 system, with computer system ubuntu 14.04, UHD >> > version 3.8.1 and gnuradio version 3.7.6. I am new to gnuradio and is >> > trying to learn how to apply it to digital signal processing theory. >> > >> > Thanks in advance for any feedback by you guys. >> > >> > Regards, >> > Wen Bin >> > >> > >> > >> > >> > >> > _______________________________________________ >> > 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 >> > > > _______________________________________________ > Discuss-gnuradio mailing > [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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