Re: [Discuss-gnuradio] how to measure ber and snr

[Marcus Müller]

Hi BZS,

haven't seen you in a long time! Welcome back :)

If you use the search tool in gnuradio-companion, you will find the BER
block, which has two inputs and will output an BER measurement.

SNR is highly dependent on what you consider to be signal and what you
consider to be noise, so for most cases you will have to make your own
Signal Power measurement and divide that by a noise power estimate.

Greetings,
Marcus

On 11.07.2014 04:18, ??? wrote:
> hi ,
> how to measure ber and snr in gnuradio ?is there any blocks about this?
> thanks,
> bzs
>
>
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Re: [Discuss-gnuradio] how to measure ber and snr

[Martin Braun]

On 07/11/2014 09:31 AM, Marcus Müller wrote:
> Hi BZS,
> 
> haven't seen you in a long time! Welcome back :)
> 
> If you use the search tool in gnuradio-companion, you will find the BER
> block, which has two inputs and will output an BER measurement.
> 
> SNR is highly dependent on what you consider to be signal and what you
> consider to be noise, so for most cases you will have to make your own
> Signal Power measurement and divide that by a noise power estimate.

That said, we have SNR estimators for certain modulations. Check the
manual, and make sure you have a basic grasp of the underlying theory
before you use them.

M

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[Discuss-gnuradio] UHD not working after clean pybombs install

[John Meloche]

Hello,

I did find a simlar entry to this problem on the forum from last month but
there was no usable solution for me unless I missed something.  Also I have
not found a way to allow me to change the USB permissions. Any advise will
be a great help.

Thanks
John

I have this issue on TWO DIFFERENT MACHINES.  Here is what I did on each of
them:

Completely fresh install of Ubuntu 12.04.4 LTS
apt-get update
apt-get upgrade
apt-get libasound2-dev (because I need to use an 8 channel USB sound card
with my GRC app)
install and configure pybombs (used all default settings)
./pybombs install gnuradio

each time I want to run gnuradio-companion I must first set the enviroment
(a minor annoyance)

./pybombs env
source /home//target/setup_env.sh
sudo /home//target/lib/uhd/utils/uhd_images_downloader.py

and then

gnuradio_companion (GRC 3.7.5 GUI works fine)

However, I have no connection to the USRP B200

uhd_find_devices or uhd_usrp_probe returns the following:

UHD Error:
 USB open failed: insufficient permisssions.
 See the application notes for your device.
No UHD Devices Found

running lsusb returns the following:

Bus 002 Device 006: ID 2500:0200

according the information in ~/target/lib/uhd/utils/uhd_usrp.rules, ID
2500:0200 is the B200 USRP
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Re: [Discuss-gnuradio] UHD not working after clean pybombs install

[Tom Rondeau]

On Fri, Jul 11, 2014 at 9:27 AM, John Meloche 
wrote:

> Hello,
>
> I did find a simlar entry to this problem on the forum from last month but
> there was no usable solution for me unless I missed something.  Also I have
> not found a way to allow me to change the USB permissions. Any advise will
> be a great help.
>
> Thanks
> John
>
> I have this issue on TWO DIFFERENT MACHINES.  Here is what I did on each
> of them:
>
> Completely fresh install of Ubuntu 12.04.4 LTS
> apt-get update
> apt-get upgrade
> apt-get libasound2-dev (because I need to use an 8 channel USB sound card
> with my GRC app)
> install and configure pybombs (used all default settings)
> ./pybombs install gnuradio
>
> each time I want to run gnuradio-companion I must first set the enviroment
> (a minor annoyance)
>
> ./pybombs env
>

You only need to run this once to create the environment setup file.


> source /home//target/setup_env.sh
>

You can put this in your ~/.bashrc (or equivalent) file to set up your
environment when you log in.


> sudo /home//target/lib/uhd/utils/uhd_images_downloader.py
>

Again, this only needs to be done once, unless the UHD images change.



>
> and then
>
> gnuradio_companion (GRC 3.7.5 GUI works fine)
>
> However, I have no connection to the USRP B200
>
> uhd_find_devices or uhd_usrp_probe returns the following:
>
> UHD Error:
>  USB open failed: insufficient permisssions.
>  See the application notes for your device.
> No UHD Devices Found
>
> running lsusb returns the following:
>
> Bus 002 Device 006: ID 2500:0200
>
> according the information in ~/target/lib/uhd/utils/uhd_usrp.rules, ID
> 2500:0200 is the B200 USRP
>

Copy the uhd_usrp.rules file into /etc/udev/rules.d/ and then reload the
udev rules:

$ sudo udevadm control --reload-rules


Tom
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Re: [Discuss-gnuradio] UHD not working after clean pybombs install

[madengr]

You may need the rtprio also.  See notes at below link I have been keeping:

http://rfpoweramp.wordpress.com/2014/06/10/setting-up-the-usrp-b200/

Note there is something screwed up with Worpress and quotes pasted from the
Linux shell, so be careful if pasting in that text.

Lou
KD4HSO


John Meloche wrote
> Hello,
> 
> I did find a simlar entry to this problem on the forum from last month but
> there was no usable solution for me unless I missed something.  Also I
> have
> not found a way to allow me to change the USB permissions. Any advise will
> be a great help.
> 
> Thanks
> John





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Re: [Discuss-gnuradio] Why am I dropping data over the UDP network?

[Marcus Leech]

Assuming that you're not just dropping samples -- are you getting 'O' on your receiver console?
 
If that isn't the case, then the most likely reason is that UDP doesn't guarantee a reliable channel, and if you're routing these UDP packets over a significant-sized IP network, that network may be dropping those packets. This is
  utterly outside the control of Gnu Radio.
 
 
 

on Jul 11, 2014, Ward, Marcus D.  wrote:


Hey Everyone,
 
I am sending a signal from one USRP to another USRP through a UDP network. It seems to work but I am getting data loss as gnu-radio runs the flow graph. Hopefully someone could help me with this problem?
 
P.S. I have the sender side (RecieveStation.jpg) and the Reciever/Display side (RecieveDisplay.jpg) attached

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Re: [Discuss-gnuradio] Why am I dropping data over the UDP network?

[Marcus Leech]

Also, you're sending data at 6.25Msps, with complex-float samples, which chews up:
 
6.25e6 x 8   bytes/second
= 400Mbit/second, without accounting for headers and other overhead.
 
You might want to re-think your architecture, if you're going to be sending this data over the network.
 
 
 

on Jul 11, 2014, Ward, Marcus D.  wrote:


Hey Everyone,
 
I am sending a signal from one USRP to another USRP through a UDP network. It seems to work but I am getting data loss as gnu-radio runs the flow graph. Hopefully someone could help me with this problem?
 
P.S. I have the sender side (RecieveStation.jpg) and the Reciever/Display side (RecieveDisplay.jpg) attached

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Re: [Discuss-gnuradio] Why am I dropping data over the UDP network?

[madengr]

Funny that I was doing the exact same thing last night, and I'm also getting
warnings on the receive end at only 500 ksps on a home LAN.

Should the stream be vectorized before the UDP sink, and if so how long?  I
tried both stream and vectors but still get the warnings.

Lou
KD4HSO


Ward, Marcus D. wrote
> Hey Everyone,
> 
> I am sending a signal from one USRP to another USRP through a UDP network.
> It seems to work but I am getting data loss as gnu-radio runs the flow
> graph. Hopefully someone could help me with this problem?
> 
> P.S. I have the sender side (RecieveStation.jpg) and the Reciever/Display
> side (RecieveDisplay.jpg) attached





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Re: [Discuss-gnuradio] Why am I dropping data over the UDP network?

[Ward, Marcus D.]

If I change the type to complex integer 16, you think I’ll have a better 
outcome? Seeing as if there is a way to change the type to complex 16, but I 
will have to incorporate converters.

From: Marcus Leech [mailto:mle...@ripnet.com]
Sent: Friday, July 11, 2014 1:38 PM
To: Ward, Marcus D.
Cc: Discuss-gnuradio@gnu.org
Subject: Re: [Discuss-gnuradio] Why am I dropping data over the UDP network?

Also, you're sending data at 6.25Msps, with complex-float samples, which chews 
up:

6.25e6 x 8   bytes/second
= 400Mbit/second, without accounting for headers and other overhead.

You might want to re-think your architecture, if you're going to be sending 
this data over the network.



on Jul 11, 2014, Ward, Marcus D. 
mailto:marcus.w...@jhuapl.edu>> wrote:
Hey Everyone,

I am sending a signal from one USRP to another USRP through a UDP network. It 
seems to work but I am getting data loss as gnu-radio runs the flow graph. 
Hopefully someone could help me with this problem?

P.S. I have the sender side (RecieveStation.jpg) and the Reciever/Display side 
(RecieveDisplay.jpg) attached



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Re: [Discuss-gnuradio] Why am I dropping data over the UDP network?

[Marcus Müller]

No, building vectors out of streams would (in the best case) change
nothing, as you don't send individual samples but always packets full of
payloads.

Also, if you have a hardware device defining your data rate, you will
never need a throttle, and having one will most likely only introduce
problems, so remove it from your flowgraph. All throttle really does is
trying to achieve a given *average* sample processing rate, and that
interferes with the hardware *constantly* providing a sample rate.

A few numbers in my head: 500ksps = 500 * 32kbps = 16000kbps, not very
much for a gigabit ethernet! So I think it's safe to assume that the
physical network is not to blame here, and usually the CPU load, maybe
introduced by network handling might be to blame, if this doesn't happen
with a null sink.

Greetings,
Marcus


On 11.07.2014 19:49, madengr wrote:
> Funny that I was doing the exact same thing last night, and I'm also getting
> warnings on the receive end at only 500 ksps on a home LAN.
>
> Should the stream be vectorized before the UDP sink, and if so how long?  I
> tried both stream and vectors but still get the warnings.
>
> Lou
> KD4HSO
>
>
> Ward, Marcus D. wrote
>> Hey Everyone,
>>
>> I am sending a signal from one USRP to another USRP through a UDP network.
>> It seems to work but I am getting data loss as gnu-radio runs the flow
>> graph. Hopefully someone could help me with this problem?
>>
>> P.S. I have the sender side (RecieveStation.jpg) and the Reciever/Display
>> side (RecieveDisplay.jpg) attached
>
>
>
>
> --
> View this message in context: 
> http://gnuradio.4.n7.nabble.com/Why-am-I-dropping-data-over-the-UDP-network-tp49283p49286.html
> Sent from the GnuRadio mailing list archive at Nabble.com.
>
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[Discuss-gnuradio] Any way to sample/log the 50Mhz ISM signal in gnuradio with USRP2?

[Yingjie Chen]

Hi guy,

Thanks in advance.

Currently I am implementing a project based on ofdm_bentchmark  example
with USRP2. I remember that the sample rate of ADC of USRP 2 with RF2450
can be up to 100MS/s. That means we can use USRP2 to capture at most 50Mhz
bandwidth signal.

Initially, I plan to log the signal on my computer (*save as dat. format)*
and analyze it offline. Everything is fine when the sample rate(bandwidth)
is set to 20MS/s in terminal. However, when we set the sample rate up to
50MS/s, nothing can be log in my computer. I guess there some software
limitations in Gnuradio.

My question is how to remove such limitation to achieve the 50MS/s sample
rate. Any help will be greatly appreciated.

Best,
Kay
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Re: [Discuss-gnuradio] Any way to sample/log the 50Mhz ISM signal in gnuradio with USRP2?

[Marcus D. Leech]

On 07/11/2014 10:20 PM, Yingjie Chen wrote:

Hi guy,

Thanks in advance.

Currently I am implementing a project based on ofdm_bentchmark 
 example with USRP2. I remember that the sample rate of ADC of USRP 2 
with RF2450 can be up to 100MS/s. That means we can use USRP2 to 
capture at most 50Mhz bandwidth signal.


Initially, I plan to log the signal on my computer (/save as dat. 
format)/ and analyze it offline. Everything is fine when the sample 
rate(bandwidth) is set to 20MS/s in terminal. However, when we set the 
sample rate up to 50MS/s, nothing can be log in my computer. I guess 
there some software limitations in Gnuradio.


My question is how to remove such limitation to achieve the 50MS/s 
sample rate. Any help will be greatly appreciated.


Best,
Kay


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To achieve 50Msps, you'll need to use 8-bit wire format, and set the 
peak= parameter appropriately.  There's just not enough bits/second on a

  1GiGe link to support 50Msps with 16-bit, full-width samples.

But you also need to consider the format you're writing samples to disk 
in, and how much disk-write bandwidth you'll require to support that.
   If you just use the same format (2 x 8bits) into the file, that's 
100Mbyte/second into the disk.  That may or may not be supportable on your

   particular system.


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Re: [Discuss-gnuradio] Any way to sample/log the 50Mhz ISM signal in gnuradio with USRP2?

[Marcus D. Leech]

On 07/11/2014 11:04 PM, Yingjie Chen wrote:

Thanks for your reply, Marcus.

8bits is enough for my case. But can you tell how to modify the adc 
from 16bits to 8bits? I have no idea where to start it on gnuradio 
example. */What to mean by setting the peak/*?? what is the notation 
of peak?



The UHD source in GRC has a parameter for setting the wire format.

http://files.ettus.com/uhd_docs/doxygen/html/structuhd_1_1stream__args__t.html

That's for the raw UHD C++ interface, but see the notes about the 
"peak=" stream argument, which you can specify in the UHD source

  block in GRC.







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