How to generate a periodic pulse


#1

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


#2

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 E. removed_email_address@domain.invalid
wrote:

Bruhtesfa

Posted via http://www.ruby-forum.com/.


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Best wishes,

Yufeng


#3

On Mon, Feb 9, 2009 at 2:11 AM, Bruhtesfa E.
removed_email_address@domain.invalidwrote:

Bruhtesfa

Posted via http://www.ruby-forum.com/.


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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


#4

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
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something that you can work out.

Karthik


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#5

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


#6

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 E.
removed_email_address@domain.invalidwrote:

Bruhtesfa

Posted via http://www.ruby-forum.com/.


Discuss-gnuradio mailing list
removed_email_address@domain.invalid
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


#7

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