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"
< address@hidden>
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
> address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
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