On Sat, May 24, 2008 at 09:13:13PM -0400, Achilleas Anastasopoulos wrote:
> Chuck, Eric,
>
> I think there is a way to perform the cPLL at 8 complex Msps and upsample
> to 16Msps only at the very end when you want to get the Real signal out for
> further processing. I believe this works (i didn't
On Sat, 2008-05-24 at 21:13 -0400, Achilleas Anastasopoulos wrote:
> Chuck, Eric,
>
> I think there is a way to perform the cPLL at 8 complex Msps and
> upsample to 16Msps only at the very end when you want to get the Real
> signal out for further processing. I believe this works (i didn't see
Chuck, Eric,
I think there is a way to perform the cPLL at 8 complex Msps and
upsample to 16Msps only at the very end when you want to get the Real
signal out for further processing. I believe this works (i didn't see
any point where there is a possibility for aliasing) and it can result
in s
On Fri, May 23, 2008 at 09:00:31AM -0400, Achilleas Anastasopoulos wrote:
> OK, I see.
>
> 1) Usually in fractional interpolators the trade-off is: more taps vs finer
> sampling. It might be possible to increase the number of taps and still be
> able to work with only a 12.8 (or 16) real-Msps.
>
On Fri, May 23, 2008 at 06:54:16AM -0400, Charles Swiger wrote:
> On Thu, 2008-05-22 at 22:35 -0700, Eric Blossom wrote:
> > On Thu, May 22, 2008 at 10:53:12PM -0400, Achilleas Anastasopoulos wrote:
> > >
> > > So the signal u(t) needs to be sampled at 6 Complex-Msps, which is what
> > > you
> >
OK, I see.
I have two comments:
1) Usually in fractional interpolators the trade-off is: more taps vs
finer sampling. It might be possible to increase the number of taps and
still be able to work with only a 12.8 (or 16) real-Msps.
Having said that, I have to admit I haven't looked at exactly
On Thu, 2008-05-22 at 22:53 -0400, Achilleas Anastasopoulos wrote:
> Chuck,
>
> I have a question regarding the comment you made in an earlier email on
> the subject:
>
> You said:
> -
> Now my question: Is it possible to tune the usrp so the carrier is at
> +.31 Mhz ? (band center a
On Thu, May 22, 2008 at 10:53:12PM -0400, Achilleas Anastasopoulos wrote:
>
> So the signal u(t) needs to be sampled at 6 Complex-Msps, which is what you
> do (sampling it at 6.4 Complex-Msps, or as Eric wants at 8 complex-Msps).
>
I'm worried about the roll off at the edges of the passband at 6.
Chuck,
I have a question regarding the comment you made in an earlier email on
the subject:
You said:
-
Now my question: Is it possible to tune the usrp so the carrier is at
+.31 Mhz ? (band center at 3, from -.2 to 6.2Mhz?) Then we could run
the cpll at 6.4 or 8Msps and get anoth
On Wed, May 21, 2008 at 07:12:39AM -0400, Charles Swiger wrote:
>
> Now my question: Is it possible to tune the usrp so the carrier is at
> +.31 Mhz ? (band center at 3, from -.2 to 6.2Mhz?) Then we could run
> the cpll at 6.4 or 8Msps and get another big performance boost, maybe.
> Right now the
On Wed, May 21, 2008 at 7:12 AM, Charles Swiger <[EMAIL PROTECTED]> wrote:
> We get a complex datastream from the usrp with signals from -3.2 to
> +3.2Mhz (6.4Mhz wide, easy /10 decimation - Eric wants 8Mhz ;).
> Previously we had to upconvert the spectrum to 5.75Mhz so that it's all
> positive fre
On Tue, 2008-05-20 at 21:55 -0400, Brian Padalino wrote:
> On Tue, May 20, 2008 at 9:38 PM, Charles Swiger <[EMAIL PROTECTED]> wrote:
> > The issue turned out to be jiggering the numbers that say "I strongly
> > suggest that you not mess with these..." * by .707 for the bit timing
> > loop worked
On Tue, May 20, 2008 at 09:38:21PM -0400, Charles Swiger wrote:
> On Tue, 2008-05-20 at 21:00 -0400, Brian Padalino wrote:
> > On Tue, May 20, 2008 at 8:52 PM, Charles Swiger <[EMAIL PROTECTED]> wrote:
> > >
> > > gr_complex IQ = input * gr_complex(a_cos,-a_sin);
> > >
> > > which would be necess
On Tue, May 20, 2008 at 9:38 PM, Charles Swiger <[EMAIL PROTECTED]> wrote:
> The issue turned out to be jiggering the numbers that say "I strongly
> suggest that you not mess with these..." * by .707 for the bit timing
> loop worked ;)
>
> We want a complex pll so it can take data directly from
On Tue, 2008-05-20 at 21:00 -0400, Brian Padalino wrote:
> On Tue, May 20, 2008 at 8:52 PM, Charles Swiger <[EMAIL PROTECTED]> wrote:
> >
> > gr_complex IQ = input * gr_complex(a_cos,-a_sin);
> >
> > which would be necessary to handle negative frequencies I think.
> >
> I don't know much about 8
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