Forum: GNU Radio how to generate a periodic pulse

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8609964d75de56552443da57880d4424?d=identicon&s=25 Bruh G. (bruh)
on 2009-02-09 11:11
Hey all,

I want to generate a periodic rectangular pulse(of low duty cycle) from
one USRP and receive it using another USRP operating simultaneously.

So, is there some built in function to generate such a pulse?
Also,what filter do i need to apply before connecting the pulse source
to Usrp sink?

Thanks!

Bruhtesfa
5d49c921fbbc3c4c04315826d9fde205?d=identicon&s=25 yufeng wang (Guest)
on 2009-02-12 19:41
(Received via mailing list)
Hey, Bruhtesfa,

This is Yufeng.  I have a more simpler question on Python, do you know
which codes can I use to generate a fixed length of random 0 and 1s,
and how to modulate them in PSK, do you have any idea about this?
Thanks!



On Mon, Feb 9, 2009 at 5:11 AM, Bruhtesfa Ebrahim <lists@ruby-forum.com>
wrote:
>
> Bruhtesfa
> --
> Posted via http://www.ruby-forum.com/.
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>



--
Best wishes,

Yufeng
B538f3568f304bb9c10b6719e1d370af?d=identicon&s=25 Karthik (Guest)
on 2009-02-12 19:55
(Received via mailing list)
On Mon, Feb 9, 2009 at 2:11 AM, Bruhtesfa Ebrahim
<lists@ruby-forum.com>wrote:

>
> Bruhtesfa
> --
> Posted via http://www.ruby-forum.com/.
>
>
> _______________________________________________
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>

You can write your own block if you aren't able to find something that
you
can plug in from gnuradio. There is a source gr.sig_source_x which
generates
square pulses, which you can modify to suit your requirements. The
actual
period of the waveform coming out of the USRP will depend on the length
of
the sequence and what your interpolation setting is. However, that is
something that you can work out.

Karthik
C8bc66d616e3503c09b25d86a84ac228?d=identicon&s=25 Jorge Miguel (jmiggal)
on 2010-10-06 13:55
Hi all,

I have the same doubt. I want to generate a pulse (with a duty cycle
less than 50%) and I do not know how to do it.

I saw gr.sig_source_x but this only generate pulses at 50% duty cicle.

I tried to multiply several squares pulses at different frequencies and
it works, I get a pulse of 12.5% duty cicle for example but it is
semi-random since all signal generators are not coherent.

Please Can somebody help me to generate a pulse signal which I can
change the pulse width?

Thanks,
Jorge.

Karthik wrote:
> On Mon, Feb 9, 2009 at 2:11 AM, Bruhtesfa Ebrahim
> <lists@ruby-forum.com>wrote:
>
>>
>> Bruhtesfa
>> --
>> Posted via http://www.ruby-forum.com/.
>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> Discuss-gnuradio@gnu.org
>> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>
> You can write your own block if you aren't able to find something that
> you
> can plug in from gnuradio. There is a source gr.sig_source_x which
> generates
> square pulses, which you can modify to suit your requirements. The
> actual
> period of the waveform coming out of the USRP will depend on the length
> of
> the sequence and what your interpolation setting is. However, that is
> something that you can work out.
>
> Karthik
C8bc66d616e3503c09b25d86a84ac228?d=identicon&s=25 Jorge Miguel (jmiggal)
on 2010-10-07 08:47
(Received via mailing list)
Hi all,

I have the same doubt. I want to generate a pulse (with a duty cycle
less than 50%) and I do not know how to do it.

I saw gr.sig_source_x but this only generate pulses at 50% duty cycle.

I tried to multiply several squares pulses at different frequencies and
it works, I get a pulse of 12.5% duty cycle for example but it is
semi-random since all signal generators are not coherent.

Please Can somebody help me to generate a pulse signal which I can
change the pulse width?

Thanks,
Jorge.



Karthik-28 wrote:
>> Also,what filter do i need to apply before connecting the pulse source
>> Discuss-gnuradio mailing list
> something that you can work out.
>
> Karthik
>
> _______________________________________________
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>

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4252201ac30d6dd44d8090ce1070e35f?d=identicon&s=25 Josh Blum (Guest)
on 2010-10-07 09:45
(Received via mailing list)
On 10/06/2010 11:47 PM, jmiggal wrote:
> semi-random since all signal generators are not coherent.
>
> Please Can somebody help me to generate a pulse signal which I can
> change the pulse width?
>

If you just want to generate a periodic waveform and your sample
rate/clock rate is an integer, you can use the vector source block (on
repeat) with the following vector for one complete cycle of the clock
waveform:
(lambda n, d, a: [a if i < d*n else 0 for i in
range(n)])(samp_rate/clk_rate, duty, ampl)

Otherwise, i suggest making a custom block in c++ or python.

-Josh
745d8202ef5a58c1058d0e5395a78f9c?d=identicon&s=25 Eric Blossom (Guest)
on 2010-10-07 09:50
(Received via mailing list)
On Wed, Oct 06, 2010 at 11:47:27PM -0700, jmiggal wrote:
> semi-random since all signal generators are not coherent.
>
> Please Can somebody help me to generate a pulse signal which I can
> change the pulse width?

  // High 12.5%
  src = gr.vector_source_f((1, 0, 0, 0, 0, 0, 0, 0), True)

  // High 25.0%
  src = gr.vector_source_f((1, 1, 0, 0, 0, 0, 0, 0), True)


Eric
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