discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] dvb-t project with two USRPN200 devices failure


From: Bogdan Diaconescu
Subject: Re: [Discuss-gnuradio] dvb-t project with two USRPN200 devices failure
Date: Mon, 31 Mar 2014 09:08:04 -0700 (PDT)


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 <address@hidden> 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
> <address@hidden>:
>> 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 <address@hidden>
>> 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
>> <address@hidden>: 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 <address@hidden>
>> 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 _______________________________________________
>> Discuss-gnuradio mailing list address@hidden
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>
>>
>>
>>
>> -- NE
>>
>>
>
>
>
>
> _______________________________________________ Discuss-gnuradio
> mailing list address@hidden
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

iQEcBAEBAgAGBQJTOZDPAAoJEBQ6EdjyzlHtDWwIALcmUMVs7Rrx/WdFtqJ//Fxn
tzMvsVrDOKBu+5AnmmbVZ20dVulN2lcZ25vZScpFYKOAbe5TwRy2XTsFODHItGNF
dhmyOQNLVArDSSQuWTLSnMODKEUMCgU/sxyDtal0SVz6KuCSjjwP/exgaKHtNweU
tQid+PdH0JTZ/5iqvtQyHJhwy0rcl0RIK8ig0MXhoQG8IQVl2lKZXUtlOle1wMsC
w5oed0uop0d1J4bWDxC3oBRd6DfSCLx9avXtCHEFdgiAZSkFPva0XhJbimm3K8GP
V6qzH2S29eojRZYQHqlWxy8ISMG8SCr0Ii2joHv6iESCB9cgK1KkWrECMc0Ltvk=
=HjFO
-----END PGP SIGNATURE-----


_______________________________________________
Discuss-gnuradio mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio



reply via email to

[Prev in Thread] Current Thread [Next in Thread]