Re: [Discuss-gnuradio] Square Wave Pulse Shapping Filter

[Andy Walls]

> Date: Sat, 19 May 2018 11:29:14 -0300
> From: Jose Marcelo Lima Duarte 

> Hello everyone,
> 
> I was giving the task of quickly develop a receiver for an old
> satellite system that use a pulse shaping filter with square wave
> impulse response and QPSK constelation.
> 
> Does GNU Radio has a prompt solution for this? By a prompt solution a
> mean a single block in GNU Radio Companion that handles carrier phase
> synch, symbol time synch and sampling. From its documentation its
> seams to me that it lacks of prompt solution for old fashion square
> wave pulse shaped signals. Am I right?

You are correct in that there is no single block in GNURadio that
handles all that.


> I have seen that GNU Radio has a prompt solution for demodulating
> QPSK signals with Squared RRC filter. And I known that it can be used
> for square wave signals too. However, I want to avoid the performance
> degradation from not using a matching filter at the receiver end.

Actually the one in GNURadio specifically can't be used for square
pulses, if it uses the Polyphase Clock Sync block in the underlying
implementation, as that block can't make a proper derivative pulse
filter for a square wave.

> Any suggestion for a quick solution for my problem?

For coarse carrier frequency synchronization, if you don't have high
doppler, the "FLL band-edge" block will keep RRC pulse filtered PSK
signals roughly on frequency.  You can probably abuse it for PSK with
square pulses too.

For matched filtering of a square pulse, just use a "Decimating FIR
Filter" block with a decimation of 1 (no decimation) and taps of
[1.0/N]*N  where N is the number of samples in th unit pulse width.
This will introduce receiver side ISI, since your square pulses are not
Nyquist pulses, but you should get nice triangular pulse peaks.

For symbol syncronization, use a "Symbol Sync" block with the signal
times slope ML approximation TED.  Also select the 8 tap MMSE
interpolation filter. 

For fine carrier frequency and phase synchronization use the "Costas
Loop" block.

Regards,
Andy 

> 

___
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

Re: [Discuss-gnuradio] gnuradio on High Sierra

[Vipin Sharma]

I tried installing gnuradio-devel. The following error still shows up. I also 
tried uninstalling the “gnuradio” and left “gnuradio-devel” installed. That 
doesn’t make any difference either.

Anything else I can try until your fix is available in the release?


Error:

/opt/local/include/cppunit/TestCaller.h:121:28: error: no member named 'bind' 
in namespace 'std'; did you mean 'find'?
m_test_function( std::bind(test, m_fixture) )

Vipin

> On May 17, 2018, at 12:02 PM, Michael Dickens  
> wrote:
> 
> Hi Vipin - Easiest way is to just install gnuradio-devel:
> {{{
> sudo port -f deactivate gnuradio
> sudo port install gnuradio-devel
> }}}
> Assuming that the 2nd command works, then in your OOT when you "make" for the 
> first time since this GR change CMake will redo configuration & you should be 
> good to go. Hope this is useful! - MLD
> 
> On Wed, May 16, 2018, at 9:57 PM, Vipin Sharma wrote:
>> Thank you. I was just trying to build a custom block in GnuRadio. GnuRadio 
>> itself is what I got from MacPorts.
>> 
>> I will wait for your fix. If the work involved more than a few days is there 
>> an alternative I can try out to bypass the issue for now?

___
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

[Discuss-gnuradio] Square Wave Pulse Shapping Filter

[Jose Marcelo Lima Duarte]

Hello everyone,

I was giving the task of quickly develop a receiver for an old satellite
system that use a pulse shaping filter with square wave impulse response
and QPSK constelation.

Does GNU Radio has a prompt solution for this? By a prompt solution a mean
a single block in GNU Radio Companion that handles carrier phase synch,
symbol time synch and sampling. From its documentation its seams to me that
it lacks of prompt solution for old fashion square wave pulse shaped
signals. Am I right?

I have seen that GNU Radio has a prompt solution for demodulating QPSK
signals with Squared RRC filter. And I known that it can be used for square
wave signals too. However, I want to avoid the performance degradation from
not using a matching filter at the receiver end. Any suggestion for a quick
solution for my problem?


Regards

-- 
José Marcelo L. Duarte
___
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

[Discuss-gnuradio] [GSoC18] gr-modtool overhaul: Blog update

[swapnil negi]

Hello everyone,
I have updated the blog

for the Week 1 updates and the tasks for week 2. Here
 is the link to the
updated Github project.
The coding period is really fun.


Thanks,
Swapnil Negi
Indian Institute of Technology Roorkee
___
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio