Hi Marcus,
What I do at the transmitter side is (QPSK signal):
pulse shaping(Root Cosine FIR Filter ) ---> resampling (where the
fractional resampler is inserted) --> low pass filter-->frequency shifter
(move the signal to the frequency it belongs to with respect to the usrp's
center frequency )
Hi Andy,
The fallacy I had in my own head was that the MMSE resampler also
filters sufficiently – I think that is not true; it's just a resampler,
you need to "select" (as in: filter everything else away) the
appropriate bandwidth yourself before.
Therefore: Yang, you'll need to filter
On Tue, 2017-10-24 at 08:16 -0400, Andy Walls wrote:
> Hi Marcus:
>
> Nice insights and plots.
>
> > From: Marcus Müller
> > Date: Mon, 23 Oct 2017 20:10:23 +0200
>
> [snip]
> > From the above figure, I'd say: go for 256 taps; 50 dB of anti-
> > aliasing should probably suffice.
> >
Hi Marcus:
Nice insights and plots.
> From: Marcus Müller
> Date: Mon, 23 Oct 2017 20:10:23 +0200
[snip]
> From the above figure, I'd say: go for 256 taps; 50 dB of anti-
> aliasing should probably suffice.
> On my machine, the 256 tap FIR filter with decimation=64 ran about
>
HI Marcus,
Thank you so much for your help!
Since there's one iteration per output sample and the number of taps of
filtering is 8 (fixed), the time it takes to do one iteration is fixed no
matter what resampling ratio I set. What slows things down is: as the
resampling ratio increase, the
Hi Yang,
for questions of performance, it's usually best to consult the source
code itself. By the way, fractional_resampler_** has been renamed
mmse_resampler_** on git's "next" branch.
You'll notice the code in {mmse_|fractional_}resampler_cc_impl.cc is:
while(oo < noutput_items)
Dear all,
I used fractional resampler(gr::filter::fractional_resampler_cc) at
transmitter side to help up sample the signal to the device sample rate
before sending it out. In the experiment, I found that this resampler works
well for some resample ratio (in terms of speed), and the performance
