gmane.comp.gnu.radio.general

Re: Question about stream tag

Tom Rondeau — 2012-05-24T14:34:26

It sounds like you need to add a rate control to your MAC layer.
Obviously, when you aren't transmitting, you don't want to be
generating any samples. You'll need to buffer them. This is going to
take some work outside of GNU Radio to create an app that has a thread
to control the samples and pass them to a message source block in GNU
Radio.

I'm not sure there's a good example of this, and we don't really have
a 'best practices' for this right now.

Tom

Question about stream tag

Pan, Luyuan — 2012-05-24T14:27:19

Hello,
     I want to use my USRP2 to implement a TDMA system, and I want to 
send 5 seconds, receive 5 seconds, and do the recycle. I used the stream 
tag demo in gr-uhd/taguhd. The question is:
1. As sean have said in 
http://lists.gnu.org/archive/html/discuss-gnuradio/2012-04/msg00506.html 
we should use "tx_time", "tx_sob" (start-of-burst), and "tx_eob" 
(end-of-burst) to tag the data flow, but yend B in 
http://www.ruby-forum.com/topic/3832986   said the data not enclosed by 
sob-eob tag pair was dropped. Is this problem really exist? And any 
solution?
2. Is there any way to switch the Tx/Rx? And how to tell the USRP to 
receive for a desired time slot such as 5 seconds then stop? The only 
parameter I can see in gr_uhd_usrp_source is 'rx_time'(tells when to 
start receive), I do not know how to stop the streaming after 5 seconds.
Thank you for your help. Any suggestion is appreciated.

Re: problem linking app with qtgui_sink_c

Tom Rondeau — 2012-05-24T13:23:06

Sure. But set_y_axis also doesn't fit, since you don't know which
y-axis you're talking about (time, waterfall, psd, etc.). Maybe
frequency_y_axis would have been better, but this was one of those
"Get it done now at all costs"(TM) type things as I recall.

It's been mentioned before that there's a rearchitecting of the gtgui
sinks going on now. As part of that, we'll try to make the many, many
properties of the sinks more accessible. I'm thinking like a keyword
lookup structure so we don't have to keep having these multiple layers
of wrapping to expose a method in a class contained down N levels.

Tom

Re: Depends for Ubuntu 12.04

Martin Braun — 2012-05-24T08:27:10

Same here, worked fine on 32-bit 12.04.

MB

Re: Depends for Ubuntu 12.04

John Boy — 2012-05-24T03:19:27

I too used build-gnuradio and it worked fine on 32-bit Ubuntu (obviously 
not AMD but i7).

          Kind Regards,

                    John

Re: Trying to read the .dat file created from the --log option of the benchmark codes

Tom Rondeau — 2012-05-24T01:31:29

On Wed, May 23, 2012 at 5:49 PM, Nazmul Islam
<mnislam< at >winlab.rutgers.edu> wrote:

Nazmul,

Have you looked at the .m file you have to see what's in it? It might
not have downloaded correctly.

Tom

Re: Any friend working on Hydra from UT austin? How about the performance.

Andrew Davis — 2012-05-24T00:55:13

I only have one USRP, and I believe only like 2% of people here have
more than one for that kind of testing, so there's not many here with
answers in this case. I saw you last thread and felt bad no one knew
the answer. Although I believe the answer could be derived from the
available bandwidth and noise.

On Wed, May 23, 2012 at 7:56 PM, Alex Zhang <cingular.alex< at >gmail.com> wrote:

what is the aux dac and aux adc used for in usrp

Page Jack — 2012-05-24T00:53:26

Hi all,
what is the aux dac and aux adc in ad9862 used for in usrp?

Regards
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Re: Any friend working on Hydra from UT austin? How about the performance.

Alex Zhang — 2012-05-23T23:56:50

Thanks Andrew, i will try to manually adjust these parameters to find the
optimized performance.
But before that, I really want to know any existing benchmark on
the performance over this GNURadio OFDM.
For example, on what kind of host-pc, what kind data rate have you reached,
with how much packet loss rate?

On Wed, May 23, 2012 at 5:29 PM, Andrew Davis <glneolistmail< at >gmail.com>wrote:

Re: problem linking app with qtgui_sink_c

Stephen — 2012-05-23T23:11:46

Now I remember how I missed this. I was wanting to change the y axis,
the decibel values, not the x axis, frequency. So I didn't look at that
routine. That routine name doesn't match what it does.

stephen

Re: Depends for Ubuntu 12.04

Marcus D. Leech — 2012-05-23T23:08:42

Unless you have comedi-compatible hardware, it's irrelevant

Re: Depends for Ubuntu 12.04

Stephen — 2012-05-23T22:52:27


On 5/23/2012 2:40 PM, Marcus D. Leech wrote:

I ran it a few weeks ago before you updated it to support 12.04. I just
had to change where the version is checked and manually install two
packages that the script could not install. One was comedi. I forgot the
other. It worked find after that. This was on a fresh install of 12.04
64bit.

stephen

Re: Any friend working on Hydra from UT austin? How about the performance.

Andrew Davis — 2012-05-23T22:29:45

I would assume GNUradio's OFDM is mathematically identical to Hydra,
have you tired finding what settings ( Channel spacing, FFT size,
Number of sub-carriers, Sub-carrier modulation scheme, symbol length,
guard interval, Sub-carrier spacing, and FEC ) hydra uses and setting
GnuRadio to that. It should yield identical throughput.

On Wed, May 23, 2012 at 12:49 PM, Alex Zhang <cingular.alex< at >gmail.com> wrote:

Re: binaries for UHD_003.004.002

Nicholas Corgan — 2012-05-23T22:19:52

The binaries for the 003.004.002 release will be online by tomorrow evening.

On 05/23/2012 03:03 PM, Zing Yu wrote:
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binaries for UHD_003.004.002

Zing Yu — 2012-05-23T22:03:14

Hello Josh,

It seems like I can't find the binaries for 


UHD_003.004.002-128-g12f7a5c9

on Ettus website. When it will be up?


Thanks. 

Yu
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Trying to read the .dat file created from the --log option of the benchmark codes

Nazmul Islam — 2012-05-23T21:49:46

I am trying to read the .dat file, created from the --log option of
benchmark_rx, in Matlab. Unfortunately, Matlab is showing errors.

I used the following command to get the file:

./benchmark_rx.py -f 450M -r 1M --log

This created the fmdemod.dat file. I downloaded the reading codes
from gnuradio-core/src/utils and ran those on the .date file in the
following way:

GNUdata=read_float_binary('fmdemod.dat');

GNUdata=read_complex_binary('fmdemod.dat');

GNUdata=read_short_binary('fmdemod.dat');

Unfortunately, all of these commands are producing the following pattern of
error:

??? Error: File: read_float_binary.m Line: 1 Column: 1  Unexpected MATLAB
operator.

How can I solve this? Any suggestion regarding reading the .dat file,
created from the benchmark_rx code, will be highly appreciated.


Thanks,

Nazmul

Re: Depends for Ubuntu 12.04

Marcus D. Leech — 2012-05-23T20:07:30

Thanks, Nick.

Curiouser and curiouser, as they say.

Re: Depends for Ubuntu 12.04

Nicholas Corgan — 2012-05-23T19:59:42

I tested the package list from the sbrac.org build-gnuradio in 32-bit 
and 64-bit Ubuntu 12.04 virtual machines, and they didn't complain about 
any of the package names.

On 05/23/2012 12:40 PM, Marcus D. Leech wrote:

Depends for Ubuntu 12.04

Marcus D. Leech — 2012-05-23T19:40:18

I'm getting (at least one) report that build-gnuradio doesn't work on 
Ubuntu 12.04 due to changes in the package names for the depends.
   So, if someone has a known "good" list of those depends, I can update 
build-gnuradio.

Cheers

Re: Maximum possible transmission rate through the benchmark code

Nazmul Islam — 2012-05-23T18:05:41

Alex,

Thanks for the email. I think that the high bitrate occuring at OFDM and
modulations except gmsk come mostly from peak to average power ratio
issues. GMSK works best for everyone, I guess.

I am just surprised to see how the uhd_fft.py is measuring the signal
strength in the 20 MHz band. I thought that the FPGA only allows 8 MHz
complex samples per second. Besides, I wonder why the narrowband
benchmark_tx shows underrun at 10 Mega Hz bandwidth whereas the OFDM
benchmark_tx doesn't show this issue at the same bit rate.

Thanks,

Nazmul

On Wed, May 23, 2012 at 12:38 PM, Alex Zhang <cingular.alex< at >gmail.com>wrote:

Re: file sink issue

Ben Reynwar — 2012-05-23T17:48:12

It depends what you mean by readable format.  If you just want to get
an idea of the values and the file isn't to big then do:

from gnuradio import gr
src = gr.file_source(1, "the_file_name")
snk = gr.vector_sink_b()
tb = gr.top_block()
tb.connect(src, snk)
tb.run()
# The bytes will be presented as a list of integers in python.
data = snk.data()
print(data)

On Tue, May 22, 2012 at 9:47 PM, ambily joseph <josephambily< at >gmail.com> wrote: