Re: [Discuss-gnuradio] Transmission time control from python level

[Josh Blum]

On 07/07/2012 09:30 AM, Nazmul Islam wrote:
> I have three USRP's and I want them to transmit a continuous stream of
> repeated GLFSR source in non-overlapping manner. In other words, each
> transmitter will transmit the source for 1 second and then pause for 5
> seconds. All transmitters will transmit during the 'odd' seconds so that
> there is a 1 second gap between the sources. This process should continue
> for ever.
> 
> Currently, I am controlling the starting and stopping time of the flow
> graphs to achieve my goals. Unfortunately, the code/flowgraph sometimes
> hangs after 15-20 starts. I am using the following code:
> 
> 
> tb = GLFSR_transmitter()   # The Tx flowgraph : GLFSR source (float) -->
> RRC filter --> USRP Sink
> 
> var = 1
> 
> while var == 1: # This process should run forever
> 
>  time.sleep(1-time.time() + int(time.time()))
> 
>  condition = ((int(time.time())%6) == 0)   # The transmitter will
> transmit after every 6 seconds
> 
>  if (condition):
> 
>   print time.time()
> 
>   tb.start()
> 
>   sleep(1)  # The transmitter runs for 1 second
> 
>   tb.stop()
> 
>   tb.wait()
> 
> 

You really dont want to stop and start the flow graph. TX streams can be
controlled with stream tags. Links to header docs and example here:
http://code.ettus.com/redmine/ettus/projects/uhd/wiki/GNU_Radio_UHD#Using-UHD-with-GNU-Radio

> My USRP's don't seem to like this frequent starting and stopping of flow
> graphs, especially when I am transmitting at 15-20 MS/s rate. I am using
> USRP N210 (SBX daughterboards) and the latest gnuradio images. What other
> things can I do to achieve this timing control? I am looking for options in
> python level since my C++ OOP background is not strong. Josh talked about
> some python based blocks (
> ttps://github.com/guruofquality/gnuradio/tree/python_blocks2)
> in (http://old.nabble.com/How-to-implement-a-TDMA-system-td33727749.html).
> They seem to be merged to the master (
> http://gnuradio.org/redmine/projects/gnuradio/repository/revisions/f8581fb475267e1a97eaab962e423559fb4bfce2)
> but I can't find the blocks.
> 

All that stuff + instructions and coding guide can be found here
https://github.com/guruofquality/grextras/wiki

-josh

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

Re: [Discuss-gnuradio] PCI Express SDR Cards and GNU Radio

[Patrik Tast]

Great work!
Connecting any RX/TX to the computer PCI "smells problems..."

I wouldn't cosider this option,
Patrik
  - Original Message - 
  From: ikjtel 
  To: discuss-gnuradio@gnu.org 
  Sent: Saturday, July 07, 2012 16:12
  Subject: Re: [Discuss-gnuradio] PCI Express SDR Cards and GNU Radio


  On Wed. Jul 4, 2012 Tom Rondeau wrote


> I only know of the Per Vices product but have not gotten my hands on
> it. But I'm really happy that they have produced their own GNU Radio
> interface for it already.
>
> My biggest question is if it's well-shielded enough for the noisy RF
> environment inside a computer chassis.
> 
> Tom


  HA HA HA - this article came out the following day.  It has a photo of *both* 
the Per Vices card *and* the person who wrote the above comment !

 
http://arstechnica.com/tech-policy/2012/07/how-software-defined-radio-could-revolutionize-wireless/2/


  Best Regards


  Max



--


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

[Discuss-gnuradio] Transmission time control from python level

[Nazmul Islam]

I have three USRP's and I want them to transmit a continuous stream of
repeated GLFSR source in non-overlapping manner. In other words, each
transmitter will transmit the source for 1 second and then pause for 5
seconds. All transmitters will transmit during the 'odd' seconds so that
there is a 1 second gap between the sources. This process should continue
for ever.

Currently, I am controlling the starting and stopping time of the flow
graphs to achieve my goals. Unfortunately, the code/flowgraph sometimes
hangs after 15-20 starts. I am using the following code:


tb = GLFSR_transmitter()   # The Tx flowgraph : GLFSR source (float) -->
RRC filter --> USRP Sink

var = 1

while var == 1: # This process should run forever

 time.sleep(1-time.time() + int(time.time()))

 condition = ((int(time.time())%6) == 0)   # The transmitter will
transmit after every 6 seconds

 if (condition):

  print time.time()

  tb.start()

  sleep(1)  # The transmitter runs for 1 second

  tb.stop()

  tb.wait()


My USRP's don't seem to like this frequent starting and stopping of flow
graphs, especially when I am transmitting at 15-20 MS/s rate. I am using
USRP N210 (SBX daughterboards) and the latest gnuradio images. What other
things can I do to achieve this timing control? I am looking for options in
python level since my C++ OOP background is not strong. Josh talked about
some python based blocks (
ttps://github.com/guruofquality/gnuradio/tree/python_blocks2)
in (http://old.nabble.com/How-to-implement-a-TDMA-system-td33727749.html).
They seem to be merged to the master (
http://gnuradio.org/redmine/projects/gnuradio/repository/revisions/f8581fb475267e1a97eaab962e423559fb4bfce2)
but I can't find the blocks.

Any suggestion will be appreciated.

Thanks,

Nazmul



-- 
Muhammad Nazmul Islam

Graduate Student
Electrical & Computer Engineering
Wireless Information & Networking Laboratory
Rutgers, USA.
___
Discuss-gnuradio mailing list
Discuss-gnuradio@gnu.org
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio

Re: [Discuss-gnuradio] PCI Express SDR Cards and GNU Radio

[Andrew Davis]

Nice pic Tom! FTA:

>It could only capture a narrow slice of spectrum: 100 kHz at most. That was 
>enough for Law and Order reruns..

How does that work :)

~Andrew

On Sat, Jul 7, 2012 at 9:22 AM, ikjtel  wrote:
>
>
>> It has a photo of *both*
>
> Well, two separate photos, if one wanted to be technical ;-)
>
> Max
>
>
> ___
> Discuss-gnuradio mailing list
> Discuss-gnuradio@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>

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

Re: [Discuss-gnuradio] PCI Express SDR Cards and GNU Radio

[ikjtel]

> It has a photo of *both* 

Well, two separate photos, if one wanted to be technical ;-)

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

Re: [Discuss-gnuradio] PCI Express SDR Cards and GNU Radio

[ikjtel]

On Wed. Jul 4, 2012 Tom Rondeau wrote

> I only know of the Per Vices product but have not gotten my hands on
> it. But I'm really happy that they have produced their own GNU Radio
> interface for it already.
>
> My biggest question is if it's well-shielded enough for the noisy RF
> environment inside a computer chassis.
> 
> Tom 


HA HA HA - this article came out the following day.  It has a photo of *both* 
the Per Vices card *and* the person who wrote the above comment !

   
http://arstechnica.com/tech-policy/2012/07/how-software-defined-radio-could-revolutionize-wireless/2/

Best Regards

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