GRC max sample rate

[Koyel Das (Vehere)]

Can GRC handle writing data from two channels of USRP at 100 MSPS each to a 
file in a RAM disk ? I am using 10G server and PCIe cable.

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Re: GRC max sample rate

[Koyel Das (Vehere)]

Hi Kyeong,

Ok thanks so much for the information.

Regards,
Koyel

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From: Kyeong Su Shin 
Sent: Friday, July 24, 2020 3:32 PM
To: Koyel Das (Vehere); GNURadio Discussion List
Subject: Re: GRC max sample rate

Hello Koyel:

I did one channel with 200 MSPS before, so probably yes (assuming that you are 
not doing any other processing).

Consider using sc16. Also, you can try using libuhd directly.

Regards,
Kyeong Su Shin

보낸 사람: Koyel Das (Vehere)  대신 Discuss-gnuradio 

보낸 날짜: 2020년 7월 24일 금요일 오후 5:59
받는 사람: GNURadio Discussion List 
제목: GRC max sample rate

Can GRC handle writing data from two channels of USRP at 100 MSPS each to a 
file in a RAM disk ? I am using 10G server and PCIe cable.

Get Outlook for iOS

Re: GRC max sample rate

[Kyeong Su Shin]

Hello Koyel:

I did one channel with 200 MSPS before, so probably yes (assuming that you are 
not doing any other processing).

Consider using sc16. Also, you can try using libuhd directly.

Regards,
Kyeong Su Shin

보낸 사람: Koyel Das (Vehere)  대신 Discuss-gnuradio 

보낸 날짜: 2020년 7월 24일 금요일 오후 5:59
받는 사람: GNURadio Discussion List 
제목: GRC max sample rate

Can GRC handle writing data from two channels of USRP at 100 MSPS each to a 
file in a RAM disk ? I am using 10G server and PCIe cable.

Get Outlook for iOS

Looking for a way to plot V_LSR vs intensity in GNU Radio

[Ellie White]

Hey all!

Hope you're doing well and having a good summer. I apologize for
cross-posting here, but I wanted to pass this question by members of both
the SARA and GNU Radio communities to see what resources are out there.
This summer I'm working as an intern for Berkeley SETI Research Center and
I'm helping integrate the Allen Array with GNU Radio. I've been collecting
data with a USRP on site and I'm now attempting to plot it.

My question is this: do any of you know of a method -- or a GNU Radio
module -- compatible with GR version 3.8 that allows you to plot raw data
from a USRP and get a plot of intensity versus velocity with respect to the
local standard of rest (V_LSR) -- instead of intensity versus frequency, as
given by the time sink block?

Thanks so much for considering this, and for any ideas you have to share!
Have a nice day and take care.

Cheers,
Ellie

-- 
Ellie White
Co-Director, Open Source Radio Telescopes
Student at Marshall University
304-654-9381
www.catseyeenterprises.net

Re: Looking for a way to plot V_LSR vs intensity in GNU Radio

[Marcus Müller]

Hi Ellie,

being not versed in radioastronomy, I need to guess a bit here, but:
Is what you want essentially "how much power is there for any Doppler 
shift"?


If that's the case, and you're observing some known-frequency emission 
(say, a Hydrogen line) would that basically amount to:


1. Frequency-Shifting so that the zero-doppler frequency ends up at 0 Hz
2. transforming your time domain observation to frequency domain
3. labeling the frequency axis so that it tells velocity?

In that case, the Qt GUI frequency case would be a way to go. You can 
set the center frequency to do 1., it inherently does 2. and 3. can be 
achieved (ignoring wrong physical unit labels) by adjusting the 
bandwidth parameter.


Cheers,
Marcus

On 24/07/2020 17.09, Ellie White wrote:

Hey all!

Hope you're doing well and having a good summer. I apologize for 
cross-posting here, but I wanted to pass this question by members of 
both the SARA and GNU Radio communities to see what resources are out 
there. This summer I'm working as an intern for Berkeley SETI Research 
Center and I'm helping integrate the Allen Array with GNU Radio. I've 
been collecting data with a USRP on site and I'm now attempting to plot it.


My question is this: do any of you know of a method -- or a GNU Radio 
module -- compatible with GR version 3.8 that allows you to plot raw 
data from a USRP and get a plot of intensity versus velocity with 
respect to the local standard of rest (V_LSR) -- instead of intensity 
versus frequency, as given by the time sink block?


Thanks so much for considering this, and for any ideas you have to 
share! Have a nice day and take care.


Cheers,
Ellie

--
Ellie White
Co-Director, Open Source Radio Telescopes
Student at Marshall University
304-654-9381
www.catseyeenterprises.net 

Re: Looking for a way to plot V_LSR vs intensity in GNU Radio

[Marcus D. Leech]

On 07/24/2020 12:17 PM, Marcus Müller wrote:

Hi Ellie,

being not versed in radioastronomy, I need to guess a bit here, but:
Is what you want essentially "how much power is there for any Doppler 
shift"?


If that's the case, and you're observing some known-frequency emission 
(say, a Hydrogen line) would that basically amount to:


1. Frequency-Shifting so that the zero-doppler frequency ends up at 0 Hz
2. transforming your time domain observation to frequency domain
3. labeling the frequency axis so that it tells velocity?

In that case, the Qt GUI frequency case would be a way to go. You can 
set the center frequency to do 1., it inherently does 2. and 3. can be 
achieved (ignoring wrong physical unit labels) by adjusting the 
bandwidth parameter.


Cheers,
Marcus

In spectro_radiometer, I use the Qt Vector plotter, and use some math to 
display km/sec on what would normally be the frequency axis.  This

  calculation doesn't account for the VLSR, but it certainly could.

error in grc but c++ code running on terminal

[Koyel Das (Vehere)]

Hi,

I am using USRP 2955. I am using the code in c++ given in github to acquire 
data. I don’t know data is correct or not but the green light below one antenna 
is glowing. However, when I run a grc flowgraph I get fpga image 
incompatibility error. Why this different behaviour while running from terminal 
and while running using grc?

Regards,
Koyel




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Re: error in grc but c++ code running on terminal

[Marcus Müller]

It's not clear which code "given in github" you're referring to. There's 
much GNU Radio code on github.


Anyway, the error you see explicitly tells you what's wrong: you're 
using the wrong version of UHD. This happens when you somehow installed 
multiple versions of UHD.


Uninstall the version that didn't come with GNU Radio.

Best regards,
Marcus

On 24/07/2020 19.24, Koyel Das (Vehere) wrote:

Hi,

I am using USRP 2955. I am using the code in c++ given in github to 
acquire data. I don’t know data is correct or not but the green light 
below one antenna is glowing. However, when I run a grc flowgraph I get 
fpga image incompatibility error. Why this different behaviour while 
running from terminal and while running using grc?


Regards,
Koyel




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Re: error in grc but c++ code running on terminal

[Koyel Das (Vehere)]

Hi Marcus,

This is the code:

https://github.com/EttusResearch/uhd/blob/master/host/examples/rx_samples_to_file.cpp

Regards,
Koyel

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From: Discuss-gnuradio  
on behalf of Marcus Müller 
Sent: Friday, July 24, 2020 10:57:05 PM
To: discuss-gnuradio@gnu.org 
Subject: Re: error in grc but c++ code running on terminal

It's not clear which code "given in github" you're referring to. There's
much GNU Radio code on github.

Anyway, the error you see explicitly tells you what's wrong: you're
using the wrong version of UHD. This happens when you somehow installed
multiple versions of UHD.

Uninstall the version that didn't come with GNU Radio.

Best regards,
Marcus

On 24/07/2020 19.24, Koyel Das (Vehere) wrote:
> Hi,
>
> I am using USRP 2955. I am using the code in c++ given in github to
> acquire data. I don’t know data is correct or not but the green light
> below one antenna is glowing. However, when I run a grc flowgraph I get
> fpga image incompatibility error. Why this different behaviour while
> running from terminal and while running using grc?
>
> Regards,
> Koyel
>
>
>
>
> Get Outlook for iOS 

Re: error in grc but c++ code running on terminal

[Marcus Müller]

As said, the problem is you have two versions of UHD installed.

> Uninstall the version that didn't come with GNU Radio.

Boundary alignment (follow up)

[lannan jiang]

Hi everyone,

Two days ago I asked something about boundary alignment, and I have been 
trying many stuff in GRC to solve this. I am stuck on this for days and any 
help will be appreciated. Below is a description of what I wish to do. 
   
   1) My transmission and receiving chain are like this: signal source -> 
constellation modulator -> Adalm Pluto Tx-> Antenna -> Adalm Pluto Rx -> 
Polyphase Clock Sync -> CMA equalizer -> Costas Loop -> decoding. As for 
modulation scheme, I am using QPSK.
2)  Now I just want to transmit  one byte output from the signal source, 
and following with one byte of a known pattern, and then one byte output from 
the signal source, etc. Then at the receiver, because i already know the known 
pattern, I need to sync to the known pattern in order to align the bytes, which 
will allow me to hear clean audio at the receiver.
3) There are three things I am looking for: 
   a.  I have been looking for a SIMPLE way  to prepend a known pattern at 
the transmitter, and send it with the output bytes of a signal source.  Is 
there any block that might work to do this in GRC?
   b.  I have been trying to see if i can write an embedded python block to 
prepend a known pattern, but I am having a hard time trying to understand the 
input_items of the block, and how i can add a known pattern iteratively.
   c. If i can successfully send the known pattern with my data to the 
receiver, is there any easy way to parse at the receiver?

  Thank you in advance! 
  Lannan 





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Re: Boundary alignment (follow up)

[Kevin McQuiggin]

Hi Lannan:

I am at about the same stage as you are with packetization and am researching 
quite similar requirements.  I spent the last few days reading and 
experimenting with some success.

There are several blocks that can help you add length tags and headers to your 
data stream.  Look at the examples in your gnuradio installation such as

/(opt or usr)/local/share/gnuradio/examples/digital/packet 

And give the several flowgraphs there a try.  There is also good associated 
reading in the gnuradio manual at:

https://www.gnuradio.org/doc/doxygen/page_packet_comms.html 


I used these materials and the principles in the example flow graphs to now 
having my QPSK transceiver almost running.  I expect that with a bit more 
effort it will be running fine early next week, as I am taking the weekend off.

The examples have stuff that you may not need like CRCs and forward error 
correction, but you could leave those out if you wish.  Focus on the packet 
length tagging and header creation, and then on the header/payload demuxing 
process.  

I have a loopback test flowgraph and am just working the bugs out of header and 
payload recovery.  It is quite detailed and the blocks need some study because, 
for example, some of the packet blocks want lengths of items in bits, while 
others want that info in bytes.  I made errors by assuming byte count when it 
turned out that the block wanted bit count.  Stuff like that.  You have to read 
about the details of each block.  

Hope this helps,

Kevin






> On Jul 24, 2020, at 2:54 PM, lannan jiang  wrote:
> 
> Hi everyone,
> 
>Two days ago I asked something about boundary alignment, and I have been 
> trying many stuff in GRC to solve this. I am stuck on this for days and any 
> help will be appreciated. Below is a description of what I wish to do. 
> 
>   1) My transmission and receiving chain are like this: signal source -> 
> constellation modulator -> Adalm Pluto Tx-> Antenna -> Adalm Pluto Rx -> 
> Polyphase Clock Sync -> CMA equalizer -> Costas Loop -> decoding. As for 
> modulation scheme, I am using QPSK.
>2)  Now I just want to transmit  one byte output from the signal source, 
> and following with one byte of a known pattern, and then one byte output from 
> the signal source, etc. Then at the receiver, because i already know the 
> known pattern, I need to sync to the known pattern in order to align the 
> bytes, which will allow me to hear clean audio at the receiver.
>3) There are three things I am looking for: 
>   a.  I have been looking for a SIMPLE way  to prepend a known pattern at 
> the transmitter, and send it with the output bytes of a signal source.  Is 
> there any block that might work to do this in GRC?
>   b.  I have been trying to see if i can write an embedded python block 
> to prepend a known pattern, but I am having a hard time trying to understand 
> the input_items of the block, and how i can add a known pattern iteratively.
>   c. If i can successfully send the known pattern with my data to the 
> receiver, is there any easy way to parse at the receiver?
> 
>  Thank you in advance! 
>  Lannan 
> 
> 
> 

Re: Boundary alignment (follow up)

[lannan jiang]

wHi Kevin, 
  Thank you for your response! 
  I have looked at those examples and specifically those blocks already and I 
have looked at the C++ API reference. But still, as you said, each block 
requires a lot of studying, and currently I am just trying to find an easier to 
prepend a known pattern at the transmitter. Perhaps I’ll go with the more 
complex examples eventually. 
  
  Thanks for you help anyway! 
  Best regards,
  Lannan 



> On Jul 24, 2020, at 10:57 PM, Kevin McQuiggin  wrote:
> 
> Hi Lannan:
> 
> I am at about the same stage as you are with packetization and am researching 
> quite similar requirements.  I spent the last few days reading and 
> experimenting with some success.
> 
> There are several blocks that can help you add length tags and headers to 
> your data stream.  Look at the examples in your gnuradio installation such as
> 
> /(opt or usr)/local/share/gnuradio/examples/digital/packet 
> 
> And give the several flowgraphs there a try.  There is also good associated 
> reading in the gnuradio manual at:
> 
> https://www.gnuradio.org/doc/doxygen/page_packet_comms.html 
> 
> 
> I used these materials and the principles in the example flow graphs to now 
> having my QPSK transceiver almost running.  I expect that with a bit more 
> effort it will be running fine early next week, as I am taking the weekend 
> off.
> 
> The examples have stuff that you may not need like CRCs and forward error 
> correction, but you could leave those out if you wish.  Focus on the packet 
> length tagging and header creation, and then on the header/payload demuxing 
> process.  
> 
> I have a loopback test flowgraph and am just working the bugs out of header 
> and payload recovery.  It is quite detailed and the blocks need some study 
> because, for example, some of the packet blocks want lengths of items in 
> bits, while others want that info in bytes.  I made errors by assuming byte 
> count when it turned out that the block wanted bit count.  Stuff like that.  
> You have to read about the details of each block.  
> 
> Hope this helps,
> 
> Kevin
> 
> 
> 
> 
> 
> 
>> On Jul 24, 2020, at 2:54 PM, lannan jiang > > wrote:
>> 
>> Hi everyone,
>> 
>>Two days ago I asked something about boundary alignment, and I have been 
>> trying many stuff in GRC to solve this. I am stuck on this for days and any 
>> help will be appreciated. Below is a description of what I wish to do. 
>> 
>>   1) My transmission and receiving chain are like this: signal source -> 
>> constellation modulator -> Adalm Pluto Tx-> Antenna -> Adalm Pluto Rx -> 
>> Polyphase Clock Sync -> CMA equalizer -> Costas Loop -> decoding. As for 
>> modulation scheme, I am using QPSK.
>>2)  Now I just want to transmit  one byte output from the signal source, 
>> and following with one byte of a known pattern, and then one byte output 
>> from the signal source, etc. Then at the receiver, because i already know 
>> the known pattern, I need to sync to the known pattern in order to align the 
>> bytes, which will allow me to hear clean audio at the receiver.
>>3) There are three things I am looking for: 
>>   a.  I have been looking for a SIMPLE way  to prepend a known pattern 
>> at the transmitter, and send it with the output bytes of a signal source.  
>> Is there any block that might work to do this in GRC?
>>   b.  I have been trying to see if i can write an embedded python block 
>> to prepend a known pattern, but I am having a hard time trying to understand 
>> the input_items of the block, and how i can add a known pattern iteratively.
>>   c. If i can successfully send the known pattern with my data to the 
>> receiver, is there any easy way to parse at the receiver?
>> 
>>  Thank you in advance! 
>>  Lannan 
>> 
>> 
>> 
> 



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