Re: [Discuss-gnuradio] how to generate a periodic pulse

[Josh Blum]

On 10/06/2010 11:47 PM, jmiggal wrote:
> 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?

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

> Thanks,
> Jorge.
>
>
>
> Karthik-28 wrote:
> > On Mon, Feb 9, 2009 at 2:11 AM, Bruhtesfa Ebrahim
> > <address@hidden>wrote:
> >
> > > 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
> > > --
> > > Posted via http://www.ruby-forum.com/.
> > >
> > >
> > > _______________________________________________
> > > Discuss-gnuradio mailing list
> > > address@hidden
> > > 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
> >
> > _______________________________________________
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