Forum: GNU Radio dvb-t project with two USRPN200 devices failure

356dfd3417bb998d945135e48409185a?d=identicon&s=25 Nasi Elda (nesazeri)
on 2014-03-31 12:23
(Received via mailing list)
Attachment: dvbt_rx_usrp_demo.grc (40 KB)
Attachment: dvbt_tx_usrp_demo.grc (30 KB)
Hi all,

I am using ubuntu 13.04, GNURADIO 3.7.
I cannot transmit or receive using two (USRPN200 + XCRV2450
d.board+VERT2450 antennas) devices for DVB-T project.
Here is the dvb-t project:  https://github.com/BogdanDIA/gr-dvbt

It will be very helpful and appreciated if you help me. If someone
tested it or can do it, please let me know. As far as I know someone
tested it with N210 model.

 I think this failure is due to high noise/interference or smt. else.
However I tested it already with all possible configurations. I also
attach my .grc files.
616d6d8c8b18b9bbd5a998ff7ae69066?d=identicon&s=25 Bogdan Diaconescu (Guest)
on 2014-03-31 17:24
(Received via mailing list)
Hi, not having access to my setup for now but for the beginning you
could try recording the spectrum with your USRP and then use the file
source to decode the signal offline. There is a script file
apps/capture.sh that I usually use to capture data. You may tweak it for
your needs (frequency, gain).

Sometimes it was reported that on old cpus the processing power is not
enough so that the result is an overflow (you directly see a long OOO
message in this case). Try to see if this is the case.

One way to reduce the overhead is to run the receiving flow directly
from command line instead of gnuradio-companion (e.g. ./top_block >
out.txt) after you have generated the flowgraph. The gnuradio-companion
cannot cope with big amount of data when the blocks gets out a lot of
text.


Bogdan




On Monday, March 31, 2014 1:22 PM, Nasi <nesazeri@mail.ru> wrote:

Hi all,

I am using ubuntu 13.04, GNURADIO 3.7.
I cannot transmit or receive using two (USRPN200 + XCRV2450
d.board+VERT2450 antennas) devices for DVB-T project.
Here is the dvb-t project:https://github.com/BogdanDIA/gr-dvbt

It will be very helpful and appreciated if you help me. If someone
tested it or can do it, please let me know. As far as I know someone
tested it with N210 model.

I think this failure is due to high noise/interference or smt. else.
However I tested it already with all possible configurations. I also
attach my .grc files.
356dfd3417bb998d945135e48409185a?d=identicon&s=25 Nasi Elda (nesazeri)
on 2014-03-31 17:38
(Received via mailing list)
Hi,

Thanks!

I am using collected data also as you say. 
I am using sampling rate of 1 Mbps instead of 10 Mbps which must be the
same for static transmission. Isn't it?




Mon, 31 Mar 2014 08:23:01 -0700 (PDT) от Bogdan Diaconescu
<b_diaconescu@yahoo.com>:
>Hi, not having access to my setup for now but for the beginning you could try
recording the spectrum with your USRP and then use the file source to decode the
signal offline. There is a script file apps/capture.sh that I usually use to
capture data. You may tweak it for your needs (frequency, gain).
>
>Sometimes it was reported that on old cpus the processing power is not enough so
that the result is an overflow (you directly see a long OOO message in this 
case).
Try to see if this is the case.
>
>One way to reduce the overhead is to run the receiving flow directly from command
line instead of gnuradio-companion (e.g. ./top_block > out.txt) after you have
generated the flowgraph. The gnuradio-companion cannot cope with big amount of
data when the blocks gets out a lot of
 text.
616d6d8c8b18b9bbd5a998ff7ae69066?d=identicon&s=25 Bogdan Diaconescu (Guest)
on 2014-03-31 17:46
(Received via mailing list)
For dvbt the bandwidth is around 9.14Msps so with the rational resampler
you need to set-up the USRP at 10Msps. 1Msps will not work as only a
part of the spectrum will be received.

Bogdan




On Monday, March 31, 2014 6:36 PM, Nasi <nesazeri@mail.ru> wrote:

Hi,

Thanks!

I am using collected data also as you say. 
I am using sampling rate of 1 Mbps instead of 10 Mbps which must be the
same for static transmission. Isn't it?




Mon, 31 Mar 2014 08:23:01 -0700 (PDT) от Bogdan Diaconescu
<b_diaconescu@yahoo.com>:

Hi, not having access to my setup for now but for the beginning you
could try recording the spectrum with your USRP and then use the file
source to decode the signal offline. There is a script file
apps/capture.sh that I usually use to capture data. You may tweak it for
your needs (frequency, gain).

Sometimes it was reported that on old cpus the processing power is not
enough so that the result is an overflow (you directly see a long OOO
message in this case). Try to see if this is the case.

One way to reduce the overhead is to run the receiving flow directly
from command line instead of gnuradio-companion (e.g. ./top_block >
out.txt) after you have generated the flowgraph. The gnuradio-companion
cannot cope with big amount of data when the blocks gets out a lot of
 text.


Bogdan




On Monday, March 31, 2014 1:22 PM, Nasi <nesazeri@mail.ru> wrote:

Hi all,

I am using ubuntu 13.04, GNURADIO 3.7.
I cannot transmit or receive using two (USRPN200 + XCRV2450
d.board+VERT2450 antennas) devices for DVB-T project.
Here is the dvb-t project: https://github.com/BogdanDIA/gr-dvbt

It will be very helpful and appreciated if you help me. If someone
tested it or can do it, please let me know. As far as I know someone
tested it with N210 model.

 I think this failure is due to high noise/interference or smt. else.
However I tested it already with all possible configurations. I also
attach my .grc files.


--
NE
356dfd3417bb998d945135e48409185a?d=identicon&s=25 Nasi Elda (nesazeri)
on 2014-03-31 17:53
(Received via mailing list)
ohhh, now I understand. 
It produces UUUU in the transmitter side - which probably means
underflow with my laptop.
Do you know how to decrease this power?



Mon, 31 Mar 2014 08:44:49 -0700 (PDT) от Bogdan Diaconescu
<b_diaconescu@yahoo.com>:
>I am using collected data also as
you say. 
>One way to reduce the overhead is to run the receiving flow directly from command
line instead of gnuradio-companion (e.g. ./top_block > out.txt) after
you have generated the flowgraph. The gnuradio-companion cannot cope
with big amount of data when the blocks gets out a lot of
 text.
7d89a70df32c0ae27c1235016f9e5441?d=identicon&s=25 Marcus Müller (Guest)
on 2014-03-31 18:00
(Received via mailing list)
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I'm afraid you can't reduce needed sample rate for a fixed bandwidth.

You need a stronger laptop. Often, plugging it into mains power helps.

Marcus

On 31.03.2014 17:52, Nasi wrote:
>> work as only a part of the spectrum will be received.
> you say.
>> offline. There is a script file apps/capture.sh that I usually
> line instead of gnuradio-companion (e.g. ./top_block > out.txt)
>> I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or
>> configurations. I also attach my .grc files.
>>
>>
>
>
>
>
> _______________________________________________ Discuss-gnuradio
> mailing list Discuss-gnuradio@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
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616d6d8c8b18b9bbd5a998ff7ae69066?d=identicon&s=25 Bogdan Diaconescu (Guest)
on 2014-03-31 18:09
(Received via mailing list)
One thing I did once and worked are:

1. Use a file sink instead of USRP when transmitting. Then, once the
file is generated send the samples from file (opened in a file source)
directly to USRP. That will need a good harddrive with at least 80MB/s
read speed, a SSD will work probably.

2. Do the above but write the file int RAM like dd if=yourfile.bin
of=/dev/ram0 - you may need to give root access. Then open /dev/ram0 in
a file source and send it to USRP. This will consume you RAM and will
potentiall lock your laptop if the .bin file is bigger than RAM size.

But, indeed you probably need a better computer.

Bogdan





On Monday, March 31, 2014 6:59 PM, Marcus Mller <marcus@hostalia.de>
wrote:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I'm afraid you can't reduce needed sample rate for a fixed bandwidth.

You need a stronger laptop. Often, plugging it into mains power helps.

Marcus

On 31.03.2014 17:52, Nasi wrote:
>> work as only a part of the spectrum will be received.
> you say.
>> offline. There is a script file apps/capture.sh that I usually
> line instead of gnuradio-companion (e.g. ./top_block > out.txt)
>> I am using ubuntu 13.04, GNURADIO 3.7. I cannot transmit or
>> configurations. I also attach my .grc files.
>>
>>
>
>
>
>
> _______________________________________________ Discuss-gnuradio
> mailing list Discuss-gnuradio@gnu.org
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
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356dfd3417bb998d945135e48409185a?d=identicon&s=25 Nasi Elda (nesazeri)
on 2014-03-31 18:13
(Received via mailing list)
Thanks a lot! I will try them too...


Mon, 31 Mar 2014 09:08:04 -0700 (PDT) от Bogdan Diaconescu
<b_diaconescu@yahoo.com>:
>
>Marcus
>>> For dvbt the bandwidth is around 9.14Msps so with the rational
>>>
>>> now but for the beginning you could try recording the spectrum
>>> with your USRP and then use the file source to decode the signal
>>> offline. There is a script file apps/capture.sh that I usually
>>> use to capture data. You may tweak it for your
 needs (frequency,
>> after you have generated the flowgraph. The gnuradio-companion
>> cannot cope with big amount of data when the blocks gets out a lot
>> of text.
>>>
>>> Bogdan
>>>
>>>
>>> On Monday,
 March 31, 2014 1:22 PM, Nasi < nesazeri@mail.ru >
>>>
>>> I think this failure is due to high
 noise/interference or smt.
>>>
>>> -- NE
>>>
>>>
>>
>>
>>
>>
>>
 _______________________________________________ Discuss-gnuradio
356dfd3417bb998d945135e48409185a?d=identicon&s=25 Nasi Elda (nesazeri)
on 2014-04-17 16:08
(Received via mailing list)
Can I trans/receive without Rational Resampler?
It distorts the signal too much :(


Mon, 31 Mar 2014 20:12:27 +0400 от Nasi <nesazeri@mail.ru>:
>>
>>I'm afraid you can't reduce needed sample rate for a fixed bandwidth.
>>>
>>>> On Monday, March 31, 2014 6:36 PM, Nasi < nesazeri@mail.ru >
>>>>
>>>>
>>>> Mon, 31 Mar 2014 08:23:01 -0700 (PDT) ?? Bogdan Diaconescu
>>>> < b_diaconescu@yahoo.com >: Hi, not having access to my setup for
>>>> now but for the beginning you could try recording the spectrum
>>>> with your USRP and then use the file source to decode the signal
>>>> offline. There is a script file apps/capture.sh that I usually
>>>> use to capture data. You may tweak it for your
 needs (frequency,
>>> after you have generated the flowgraph. The gnuradio-companion
>>> cannot cope with big amount of data when the blocks gets out a lot
>>> of text.
>>>>
>>>> Bogdan
>>>>
>>>>
>>>> On Monday,
 March 31, 2014 1:22 PM, Nasi < nesazeri@mail.ru >
>>>>
>>>> I think this failure is due to high
 noise/interference or smt.
>>>>
>>>> -- NE
>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
 _______________________________________________ Discuss-gnuradio
95407eef371d1aa1a5696f52c8d70a0e?d=identicon&s=25 Ron Economos (Guest)
on 2014-04-18 00:54
(Received via mailing list)
Yes, it's possible. The use of the rational re-sampler
is to be compatible with commercial DVB-T receivers.
If you're just interested in USRP to USRP, then it's
okay to use a 10 Msps sample rate. The signal will
be slightly wider than a standard 8 MHz signal at
9.142857 Msps.

You can modify my DVB-T Transport Stream bitrate
calculator to determine the required bitrates at 10 Msps.

https://github.com/drmpeg/dtv-utils/blob/master/dvbtrate.c

Ron
356dfd3417bb998d945135e48409185a?d=identicon&s=25 Nasi Elda (nesazeri)
on 2014-04-20 17:41
(Received via mailing list)
Not actually, not possible. I tested today. It does not receive
anything.


Thu, 17 Apr 2014 15:53:39 -0700 от Ron Economos <w6rz@comcast.net>:
>https://github.com/drmpeg/dtv-utils/blob/master/dvbtrate.c
>>>Thanks a lot! I will try them too...
>>>
>>>
>>>Mon, 31 Mar 2014 09:08:04 -0700 (PDT) от Bogdan
                Diaconescu  <b_diaconescu@yahoo.com> :
>>>>
>>>>One thing I did once and worked are:
>>>>
>>>>1. Use a file sink instead of USRP when
                            transmitting. Then, once the file is
                            generated send the samples from file (opened
                            in a file source) directly to USRP. That
                            will need a good harddrive with at least
                            80MB/s read speed, a SSD will work probably.
>>>>
>>>>2. Do the above but write the file int RAM
                            like dd if=yourfile.bin of=/dev/ram0 - you
                            may need to give root access. Then open
                            /dev/ram0 in a file source and send it to
                            USRP. This will consume you RAM and will
                            potentiall lock your laptop if the .bin file
                            is bigger than RAM size.
>>>>
>>>>But, indeed you probably need a better
                            computer.
>>>>
>>>>Bogdan
>>>>
>>>>
>>>>
>>>>On Monday, March 31,
                                      2014 6:59 PM, Marcus Müller
<marcus@hostalia.de> wrote:
>>>>-----BEGIN PGP SIGNED
                                    MESSAGE-----
>>>>Hash: SHA1
>>>>
>>>>I'm afraid you can't reduce needed
                                    sample rate for a fixed bandwidth.
>>>>
>>>>You need a stronger laptop. Often,
                                    plugging it into mains power helps.
>>>>
>>>>Marcus
>>>>
>>>>On 31.03.2014 17:52, Nasi wrote:
>>>>> ohhh, now I understand. It
                                    produces UUUU in the transmitter
                                    side -
>>>>> which probably means underflow
                                    with my laptop. Do you know how to
>>>>> decrease this power?
>>>>>
>>>>>
>>>>>
>>>>> Mon, 31 Mar 2014 08:44:49 -0700
                                    (PDT) ?? Bogdan Diaconescu
>>>>> < b_diaconescu@yahoo.com >:
>>>>>> For dvbt the bandwidth is
                                    around 9.14Msps so with the rational
>>>>>> resampler you need to
                                    set-up the USRP at 10Msps. 1Msps
                                    will not
>>>>>> work as only a part of the
                                    spectrum will be received.
>>>>>>
>>>>>> Bogdan
>>>>>>
>>>>>>
>>>>>> On Monday, March 31, 2014
                                    6:36 PM, Nasi < nesazeri@mail.ru >
>>>>>> wrote: Hi,
>>>>>>
>>>>>> Thanks!
>>>>>>
>>>>>> I am using collected data
                                    also as
>>>>> you say.
>>>>>> I am using sampling rate of
                                    1 Mbps instead of 10 Mbps which must
>>>>>> be the same for static
                                    transmission. Isn't it?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Mon, 31 Mar 2014 08:23:01
                                    -0700 (PDT) ?? Bogdan Diaconescu
>>>>>> < b_diaconescu@yahoo.com >:
                                    Hi, not having access to my setup
                                    for
>>>>>> now but for the beginning
                                    you could try recording the spectrum
>>>>>> with your USRP and then use
                                    the file source to decode the signal
>>>>>> offline. There is a script
                                    file apps/capture.sh that I usually
>>>>>> use to capture data. You
                                    may tweak it for your needs
                                    (frequency,
>>>>>> gain).
>>>>>>
>>>>>> Sometimes it was reported
                                    that on old cpus the processing
                                    power
>>>>>> is not enough so that the
                                    result is an overflow (you directly
                                    see
>>>>>> a long OOO message in this
                                    case). Try to see if this is the
>>>>>> case.
>>>>>>
>>>>>> One way to reduce the
                                    overhead is to run the receiving
                                    flow
>>>>>> directly from command
>>>>> line instead of
                                    gnuradio-companion (e.g. ./top_block
                                    > out.txt)
>>>>> after you have generated the
                                    flowgraph. The gnuradio-companion
>>>>> cannot cope with big amount of
                                    data when the blocks gets out a lot
>>>>> of text.
>>>>>>
>>>>>> Bogdan
>>>>>>
>>>>>>
>>>>>> On Monday, March 31, 2014
                                    1:22 PM, Nasi < nesazeri@mail.ru >
>>>>>> wrote: Hi all,
>>>>>>
>>>>>> I am using ubuntu 13.04,
                                    GNURADIO 3.7. I cannot transmit or
>>>>>> receive using two (USRPN200
                                    + XCRV2450 d.board+VERT2450
                                    antennas)
>>>>>> devices for DVB-T project.
                                    Here is the dvb-t project:
>>>>>>  https://github.com/BogdanDIA/gr-dvbt
>>>>>>
>>>>>> It will be very helpful and
                                    appreciated if you help me. If
>>>>>> someone tested it or can do
                                    it, please let me know. As far as I
>>>>>> know someone tested it with
                                    N210 model.
>>>>>>
>>>>>> I think this failure is due
                                    to high noise/interference or smt.
>>>>>> else. However I tested it
                                    already with all possible
>>>>>> configurations. I also
                                    attach my .grc files.
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