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Re: Issue in pack repack block? (former Issue in file sink block)


From: Maitry Raval
Subject: Re: Issue in pack repack block? (former Issue in file sink block)
Date: Mon, 23 Nov 2020 16:43:22 +0530 (IST)

Hello,

Yes, I understand both the points. and we are working on the installation of GR 3.8. 
In parallel, I have done implementation of QPSK demodulation( please find attached grc file ) , I have followed below points.

1. QPSK( without differential encoding) and with filter=1 modulated carrier transmission with carrier frequency of 2 GHz with data rate of 528 ksps.
2. Receive and record the same with fmcomm source block and file sink with 1.056 Msps ( as samples/symbol will be 4) 
3. offline qpsk demodulation with the attached GRC file to receive the transmitted binary sequence in file sink and convert it to binary.
But, when I have done that, the data of the output file is some random not as transmitted. as of now i am doing transmitter and receiver interfacing via RF cable( bench test) , so I don't think there may ne any noise related issue.

I think , there is an issue of sync between transmitter and receiver/recorded via FMComm source block.

Kindly guide as I want to use external transmitter for QPSK modulation and GNU radio with SDR for QPSK demodulation and data storage. 

Please help what I am missing over here/


With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Christophe Seguinot" <christophe.seguinot@orange.fr>
To: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Cc: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Monday, November 23, 2020 2:54:56 PM
Subject: Re: Issue in pack repack block? (former Issue in file sink block)

Hi

>> the starting bit of the sequence is random from the transmitted 12 bit sequence

Yes in any receiver, first received bits are corrupted and unusable (the receiver takes some time to synchronize carrier frequency and do symbol timing recovery) . if you know a part of the transmitted bits let call if a starting_sequence, you can use  correlation of starting_sequence and output to find out the starting_sequence inside output bits..

regards

On 23/11/2020 07:07, Maitry Raval wrote:
Dear Sir,

Thank you for the response. 

GNU 3.8 version debugging is under process. In parallel, I have implemented the attached GRC file as per given suggestion from your end.
After that, I have received the output file same as transmitting sequence. I have checked it in https://mothereff.in/binary-ascii.
But, only issue is that, the stored starting bits are different ( please find attached stored output file for transmitting sequence: 1001100011101. ) you will see a starting bits are different, if we convert that to binary 

We will get a invalid data. 

also , the starting bit of the sequence is random from the transmitted 12 bit sequence. so, when we transmit more bits (long transmitting sequence or any random sequence) it is very hard to find the starting bit.

Is it because of the GNU radio version we are using or any other issue or the use of ASCII to binary converter? I don't understand , please guide.

Thank you for your support in advance.

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Christophe Seguinot" <christophe.seguinot@orange.fr>
To: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Sent: Friday, November 20, 2020 4:59:54 PM
Subject: Re: Issue in pack repack block? (former Issue in file sink block)

HI,

As I don't use Widows, I could not realy at this.

Its seems this error is not related to GR but see here 53 last posts) if ti can help or ask on the discuss list

https://forum.qt.io/topic/110540/qt-qpa-plugin-could-not-find-the-qt-platform-plugin-windows-in-qtlib-plugins-platforms/15

regards

On 20/11/2020 08:40, Maitry Raval wrote:
Dear Sir,

I have done the installation of 3.8 GNU radio version in order to implement the same that you are saying in the previous mail. But, it seems to have problem in QT GUI initialization with 3.8 version of GNU radio. I have attached the snapshot for your reference. Please guide.

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Christophe Seguinot" <christophe.seguinot@orange.fr>
To: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Sent: Friday, November 13, 2020 2:38:37 PM
Subject: Re: Issue in pack repack block? (former Issue in file sink block)

I forget to mention that I was not able to use an online ascii2bin decoder (i tested https://www.rapidtables.com/convert/number/ascii-to-binary.html).

I used okteta (Linux tool).


On 13/11/2020 08:46, Maitry Raval wrote:
Dear Sir,

I have tried as per given suggestion from you by using unpack =1 followed by repack with k=1, I=8 with MSB endianness . Please find attached for your reference.but didnot get the expected result. 

Please guide. 

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Christophe Seguinot" <christophe.seguinot@orange.fr>
Cc: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Sent: Thursday, November 12, 2020 9:06:44 PM
Subject: Re: Issue in pack repack block? (former Issue in file sink block)

May be you should replace your repack block with:

  • on unpack with k=1 (i did that to recover bits)
  • and a repack with k=1, l=8, and MSB Endianness


On 12/11/2020 16:17, Christophe Seguinot wrote:

Hi,

I've been investigating the pack /unpack /repack block since the problem raised by Maitry where not  originating from modulation/demodulation (which I tested and was correct).

  • Maitry did some test using repetitive pattern of bits  such as 1100, 1010,, and lead to the conclusion that its file sink was correct (*).
  • I did similar test with small repetitive pattern but found that only some of them give correct file sink (see explanation further)

From this it seems that somewhere in its flowgraph bytes to bit or bits to bytes conversion.

The attached flowgraph (GR 3.8 and 3.9, not compatible with GR 3.7) illustrates my investigation. Running this flowgraph shows that whatever conversion is in use give the same series of bytes and bits.

However, in order to obtain this I had to set endianness to MSB for both repack blocks (all other blocks set to LSB). Il all endianness are set to LSB, repack blogk reverse bit ordering compared to pack/unpack blocks, OR uses symmetric pattern as Maitry does (*).

  • I was expecting that unpack(8) and repack(8,1) should give the same result
  • What am I missing or misunderstanding ?
  • Or is this a bug?

Maitry, please try to set Endianness to MSB in your repack block. Not sure it cans solve your issue!

Regards,



On 11/11/2020 09:30, Maitry Raval wrote:
Dear sir,

Thank you for your response.

As I have a final application to use only demodulation and data storage using GNU radio as my transmitter is external. after that also I am facing an issue for stored data which is random not as transmitted. so request you to please guide me further in this demodulation.

Thank you in advance

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Christophe Seguinot" <christophe.seguinot@orange.fr>
To: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Cc: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Wednesday, November 11, 2020 1:53:34 PM
Subject: Re: Issue in file sink block

Hi

I've been investigating but did not yet found the origin of this problem. I'm working under GR 3.9/Ubuntu 20.04

  • the bit sequence is correctly demodulated, whatever the source (txt or random) is. There is a 58 sample delay between bit source and demodulated bit. (so modulation/demodulation is OK)
  • however, the received bytes don't match the emitted bytes.
  • I'm further investigating if "pack bits" and "unpack bits" block are used correctly (I'm not familiar to them)

Regards

On 11/11/2020 04:25, Maitry Raval wrote:
Hello,

I think there is some misunderstanding here, I am using the attached grc file which includes all the ok blocks such as polyphase clock sync, costas loop, CMA equilizer etc for demodulation. Please check the attached file. for the attached grc, I am facing the below issue.

I understand that I have use online ASCII to binary converter and for that I am using below online converter.

But I am facing an issue, while I am transmitting repetitive pattern such as 1100, 1010 , the data stored in the file after mod-demod is almost similar( only some initial bits are changed) . Please check the screenshot attached. 

But when I am transmitting some random pattern instead of repetitive using file source, I am not receiving the same pattern, while I am converting the stored ASCII to binary using converter. 

Please help.

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Cinaed Simson" <cinaed.simson@gmail.com>
To: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Cc: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Wednesday, November 11, 2020 12:51:54 AM
Subject: Re: Issue in file sink block

Hi Maitry - okay, then Marcus has already updated you - DPSK Mod is depreciated.

That is, it has bugs which can't or won't be fixed and is no longer supported.

-- Cinaed



On 11/9/20 7:43 PM, Maitry Raval wrote:
Hello,

I understand that I have use online ASCII to binary converter and for that I am using below online converter.

But I am facing an issue, while I am transmitting repetitive pattern such as 1100, 1010 , the data stored in the file after mod-demod is almost similar( only some initial bits are changed) . Please check the screenshot attached. 

But when I am transmitting some random pattern instead of repetitive using file source, I am not receiving the same pattern, while I am converting the stored ASCII to binary using converter. 

 I have sent the GRC file in previous mail. Kindly let me know, where is the problem?

Waiting for your positive response.

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Cinaed Simson" <cinaed.simson@gmail.com>
To: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Monday, November 9, 2020 1:15:51 PM
Subject: Re: Issue in file sink block

Hi Maitry - if by update you mean dumping a binary file as binary instead of hexadecimal, then on Linux  use

  xxd -b <infile> <outfile>

-- Cinaed


On 11/8/20 8:13 PM, Maitry Raval wrote:
Hello experts,

Any updates?

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Aditya Arun Kumar" <adityaarunkumarphi@gmail.com>
To: "Maitry Raval" <maitry.raval@azistaaerospace.com>
Cc: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Wednesday, November 4, 2020 11:46:32 AM
Subject: Re: Issue in file sink block

Ok, thanks. 

On Wed, Nov 4, 2020 at 11:28 AM Maitry Raval <maitry.raval@azistaaerospace.com> wrote:
Hello,

Please ignore the previous grc file. please find attached the correct grc file.

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Maitry Raval" <maitry.raval@azistaaerospace.com>
To: "Aditya Arun Kumar" <adityaarunkumarphi@gmail.com>
Cc: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Wednesday, November 4, 2020 9:06:09 AM
Subject: Re: Issue in file sink block

Hello, 

Please find attached grc file for reference. I have done trial and error by converting the output file into online ascii to binary converter, but it provides random output. 

Please guide which binary viewer I need to use in  check the data in 1 and 0 format(binary) ? 

With Best Regards,
Maitry Raval,
R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com


From: "Aditya Arun Kumar" <adityaarunkumarphi@gmail.com>
To: "Derek Kozel" <derek@bitstovolts.com>
Cc: "Maitry Raval" <maitry.raval@azistaaerospace.com>, "Marcus Müller" <mmueller@gnuradio.org>, "discuss-gnuradio" <discuss-gnuradio@gnu.org>
Sent: Tuesday, November 3, 2020 5:49:05 PM
Subject: Re: Issue in file sink block

Or maybe use a gr-baz any sink to view bits?

On Tue, Nov 3, 2020 at 5:43 PM Derek Kozel <derek@bitstovolts.com> wrote:
Hello Maitry,

The File Sink is not producing a text file, it is the raw binary data.
You need to look at the contents of the file using a binary viewer.

Regards,
Derek

On 03/11/2020 11:12, Maitry Raval wrote:
> Hello sir,
>
> Please find attached screenshot for the grc file same as given in PSK guided tutorials. also, I have attached output txt file for your reference. still , did not receive binary data stored via file sink.
>
> Please guide, where am I doing wrong.
>
>
> With Best Regards,
> Maitry Raval,
> R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com
>
> ----- Original Message -----
> From: "Marcus Müller" <mmueller@gnuradio.org>
> To: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
> Sent: Monday, November 2, 2020 8:47:28 PM
> Subject: Re: Issue in file sink block
>
> Again, the file sink is fine.
>
> On 02.11.20 04:39, Maitry Raval wrote:
>> Hello,
>>
>> I understand, I think, I need to use PSK demod using below link.
>> https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation
>>
>> But, as I have a requirement of storing the demod data in file , how is it possible using file sink or any other way, please guide.
>>
>> With Best Regards,
>> Maitry Raval,
>> R& D engineer|Azista Industries Pvt Ltd| 079-40605800|www.azistaaerospace.com
>>
>> ----- Original Message -----
>> From: "Marcus Müller, CEL" <mueller@kit.edu>
>> To: "discuss-gnuradio" <discuss-gnuradio@gnu.org>
>> Sent: Saturday, October 31, 2020 9:06:22 PM
>> Subject: Re: Issue in file sink block
>>
>> Hi Maitry,
>>
>> I doubt it's the file sink. That tutorial used DPSK Mod, and that's
>> among the buggy packet_encoder tooling that we deprecated a long time
>> ago, and finally banished two-ish years ago. It just dropped data.
>>
>> See the more modern packet examples that come with your GNU Radio 3.8.
>>
>> Cheers,
>> Marcus
>>
>> On 31.10.20 09:34, Maitry Raval wrote:
>>> Hello ,
>>>
>>> I am using GNU radio along with ADRV9361-Z7035 Board for data reception
>>> and demodulation. I have faced an issue of using file sink block along
>>> with QPSK demod blocks. when I am attaching dpsk/PSK demod block with
>>> file sink, I have not received data in binary format. it gives some
>>> trunk values. when I am doing wrong, please guide us.
>>> I have taken a reference of below link.
>>> https://courses.washington.edu/ee420/projects/lab2_gnuradio.pdf
>>>
>>> The only difference is that I am using receiving section only. as I am
>>> transmitting from other source. so I have attached fmcommsource block
>>> with dpsk demod followed by file sink.
>>>
>>> Please guide
>>>
>>> With Best Regards,
>>> Maitry Raval,
>>> R& D engineer|Azista Industries Pvt Ltd|
>>> 079-40605800|www.azistaaerospace.com
> >




--
S. Aditya Arun Kumar
Security Researcher, Comms
+919123517465


--
S. Aditya Arun Kumar
Security Researcher, Comms
+919123517465





Attachment: QPSK_demod.grc
Description: XML document


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