[Discuss-gnuradio] voice over digital moduation

2017-11-09 Thread Atif Javed 
Hi

I have been working with Gnuradio and USRP N200 for about a month now and
about all this time I have never succeeded in transmitting digital voice
via USRP. My Proposed approach is like

audio source--->CVSD encoder>OFDM mod-->rational resample to
200k--->multiply with signal source (100k)-->USRP sink

on the receiver side

USRP source--> multiply with signal source (100k)--..rational
resample to 48k --->low pass filter->OFDM demod-->CVSD decoder
--->audio sink


I have also used a built in flowgraph of OFDM voice attached within where i
get zero output with  encoder (codec 2). If the encoder is disabled, the
output works just fine.
Any kind of assistance in this regard would be much appreciated.

Regards
ATIF JAVED


OFDM_voice.grc
Description: Binary data
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Re: [Discuss-gnuradio] Sampling rate of gr-ieee 802.15.4

2017-11-09 Thread Bastian Bloessl 
Hi,

> On 9. Nov 2017, at 17:25, Sumit Kumar  wrote:
> 
> Hi, 
> 
> The 802.15.4 spec says that the channels should be 2 MHz wide with 5 MHz 
> inter channel spacing. 
> 
> Why does gr-ieee 802.15.4 uses a sampling rate of 4MHz instead of 2 MHz ? 
> 
> Off course it works with commercial devices, but I am curious why 4 MHz and 
> not 2 MHz. 

With 4Mhz, the receiver samples the signal at a rate of 2 samples per chip. You 
could also use less or more, it’s a trade-off between computational complexity 
and performance.

Best,
Bastian
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[Discuss-gnuradio] Serious bug in tag propagation with non-integer relative rate

2017-11-09 Thread Eugene Grayver 
There is a major problem with the way tags are propagated in blocks with 
non-integer relative rate. If the ratio is not a power of two, the numerical 
accuracy of the floating point will cause the output tags to diverge from the 
input tags.  Consider the fractional resampler. It accumulates the timing 
offset in the range of 0 to 1. However tag propagation multiplies the ratio by 
the sample number. As the sample number grows the LSB accuracy of the ratio 
gets scaled by the ever larger value. For a ratio of 1.001 we saw divergence of 
1000s of samples over a few minutes at 10msps. I rewrote tag propagation for 
the resampler but did not rework the generic logic. I think the key point is to 
use the delta between read and written items to take out the large integer 
difference and then apply the scaling to a local delta within the current 
window.

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Aerospace Corp., Sr. Eng. Spec.
Tel: 310.336.1274


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Re: [Discuss-gnuradio] Cyberspectrum Software Defined Radio Meetup (South Bay, Wed Nov 15th, 7:30PM PT)

2017-11-09 Thread Balint Seeber 
Dear all,

Please see correct link: https://www.meetup.com/Cyberspectrum/events/244958759/

Thank you to Nick Foster for pointing that out.

> On 9 Nov 2017, at 7:31 am, Neel Pandeya  wrote:
> 
> Just wanted to note that space at the Cyberspectrum event on Wednesday is 
> limited, so you have to RSVP on the Meetup page by Wednesday morning.
> 
> Thanks a lot!
> 
> --​Neel Pandeya
> 
> 
> 
>> On 9 November 2017 at 07:12, Balint Seeber  wrote:
>> Dear all,
>> 
>> We're hosting a special meetup next week in the South Bay! It's the same 
>> week as the DARPA Bay Area SDR Hackfest: 
>> https://darpahackfest.com/bay-area-hackfest
>> 
>> Please get in touch if you would like to present.
>> 
>> Event details can be found here: 
>> https://www.meetup.com/Cyberspectrum/events/243307509/
>> Don't forget all our videos are here: 
>> https://www.youtube.com/playlist?list=PLPmwwVknVIiXGzKhtimTMjhcyppeRRsnE
>> 
>> ...and materials here: http://www.meetup.com/Cyberspectrum/about/
>> 
>> For updates before, and photos during the event: 
>> https://twitter.com/spenchdotnet
>> 
>> Please support Cyberspectrum by submitting a talk, requesting a 
>> topic/presenters, or spreading the word about us!
>> 
>> If you would like to learn more about setting one up, please get in touch. 
>> (Anyone on the US East Coast?)
>> 
>> If you're not familiar with Cyberspectrum: "The Bay Area SDR Meetup will 
>> serve as a forum to exchange knowledge and ideas related to Software Defined 
>> Radio (the software and hardware), and generally aim to get people excited 
>> about all the applications that can be realised with the technology. At each 
>> meetup, attendees will have the opportunity to present their work/ideas to 
>> the group. Engineers, enthusiasts, hobbyists and people of all experience 
>> levels are welcome, no matter what your software/hardware background."
>> 
>> As always, if you would like to present at a future event about a project 
>> you're working on, or something interesting you've discovered, please get in 
>> touch!
>> 
>> Stay tuned and hope to see you there,
>> Balint
>> 
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[Discuss-gnuradio] Sampling rate of gr-ieee 802.15.4

2017-11-09 Thread Sumit Kumar 
Hi,

The 802.15.4 spec says that the channels should be 2 MHz wide with 5 MHz
inter channel spacing.

Why does gr-ieee 802.15.4 uses a sampling rate of 4MHz instead of 2 MHz ?

Off course it works with commercial devices, but I am curious why 4 MHz and
not 2 MHz.

Regards

Sumit
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Re: [Discuss-gnuradio] Cyberspectrum Software Defined Radio Meetup (South Bay, Wed Nov 15th, 7:30PM PT)

2017-11-09 Thread Neel Pandeya 
Just wanted to note that space at the Cyberspectrum event on Wednesday is
limited, so you have to RSVP on the Meetup page by Wednesday morning.

Thanks a lot!

--​Neel Pandeya



On 9 November 2017 at 07:12, Balint Seeber  wrote:

> Dear all,
>
> We're hosting a special meetup next week in the South Bay! It's the same
> week as the DARPA Bay Area SDR Hackfest: https://
> darpahackfest.com/bay-area-hackfest
>
> Please get in touch if you would like to present.
>
> Event details can be found here: https://www.meetup.com/C
> yberspectrum/events/243307509/
>
> Don't forget all our videos are here: https://www.youtube.com/
> playlist?list=PLPmwwVknVIiXGzKhtimTMjhcyppeRRsnE
>
> ...and materials here: http://www.meetup.com/Cyberspectrum/about/
>
> For updates before, and photos during the event: https://twitter.com/spe
> nchdotnet
>
> Please support Cyberspectrum by submitting a talk, requesting a
> topic/presenters, or spreading the word about us!
>
> If you would like to learn more about setting one up, please get in touch.
> (Anyone on the US East Coast?)
> If you're not familiar with Cyberspectrum: "The Bay Area SDR Meetup will
> serve as a forum to exchange knowledge and ideas related to Software
> Defined Radio (the software and hardware), and generally aim to get people
> excited about all the applications that can be realised with the
> technology. At each meetup, attendees will have the opportunity to present
> their work/ideas to the group. Engineers, enthusiasts, hobbyists and people
> of all experience levels are welcome, no matter what your software/hardware
> background."
>
> As always, if you would like to present at a future event about a project
> you're working on, or something interesting you've discovered, please get
> in touch!
>
> Stay tuned and hope to see you there,
> Balint
>
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>
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[Discuss-gnuradio] Cyberspectrum Software Defined Radio Meetup (South Bay, Wed Nov 15th, 7:30PM PT)

2017-11-09 Thread Balint Seeber 
Dear all,

We're hosting a special meetup next week in the South Bay! It's the same
week as the DARPA Bay Area SDR Hackfest:
https://darpahackfest.com/bay-area-hackfest

Please get in touch if you would like to present.

Event details can be found here: https://www.meetup.com/
Cyberspectrum/events/243307509/

Don't forget all our videos are here: https://www.youtube.com/
playlist?list=PLPmwwVknVIiXGzKhtimTMjhcyppeRRsnE

...and materials here: http://www.meetup.com/Cyberspectrum/about/

For updates before, and photos during the event: https://twitter.com/spe
nchdotnet

Please support Cyberspectrum by submitting a talk, requesting a
topic/presenters, or spreading the word about us!

If you would like to learn more about setting one up, please get in touch.
(Anyone on the US East Coast?)
If you're not familiar with Cyberspectrum: "The Bay Area SDR Meetup will
serve as a forum to exchange knowledge and ideas related to Software
Defined Radio (the software and hardware), and generally aim to get people
excited about all the applications that can be realised with the
technology. At each meetup, attendees will have the opportunity to present
their work/ideas to the group. Engineers, enthusiasts, hobbyists and people
of all experience levels are welcome, no matter what your software/hardware
background."

As always, if you would like to present at a future event about a project
you're working on, or something interesting you've discovered, please get
in touch!

Stay tuned and hope to see you there,
Balint
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[Discuss-gnuradio] Setting output buffer to contain one packet

2017-11-09 Thread Muhammad Zulqarnain 
Dear All!

I am new to GNU-Radio. I have previously used MATLAB for packet transmission 
and detection. Here is the problem, I am facing:

I have inserted zeros between the packets and transmitting the same packet over 
and over again. In the packet formation, I have appended two preambles 
side-by-side and using auto-correlation approach to detect coarse estimate of 
frequency and start of the packet. This was already done in MATLAB, but in 
GNURadio I am stuck in buffer things. I want the output buffer to contain 
exactly one packet so I can do processing on each packet (i.e. doing 
synchronization, demodulating etc.)

My approach of doing auto-correlation is similar to Schmidl & Cox 
synchronization but all I find in GNURadio is for OFDM. Where this is a case of 
simple packetized transmission.

As I am inserting zeros between the packets so detection of individual packets 
at the receiver won't be a problem.

I have already set the max output buffer to packet length i.e.  
set_max_noutput_items (495);

Here is what I am doing in work function. but somehow I am not getting any 
output.


  float curr_sample;
  int i =0;
  int y = 0;
  // Do <+signal processing+>
  while(i<=noutput_items){
curr_sample = abs(in[y]);
  if (curr_sample >= 0.5 && packet_start == 0){ //0.5 is the threshold 
that signal is coming
packet_start = 1;
packet_length_count = 0;
  }
  if (packet_start == 1){
  out[i] = in[y];
  packet_length_count++;
  i++;
  }
  if (curr_sample <= 0.2 && packet_start == 1){  //0.2 is the threshold 
that zero is coming
  packet_start = 0;
  packet_length_count = 0;
//  printf("curr_packet_length: %d \n",packet_length_count);
  return i;
  }
y++;
  }
  consume_each (y);



Awaiting reply!

Regards,
Muhammad Zulqarnain
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