[USRP-users] [Discuss-gnuradio] New UHD seems to break a lot...

Ian Buckley ianb at ionconcepts.com
Fri Apr 17 21:44:58 EDT 2015


Ralph,
I'm not able to access either of the .grc files on your website, but using the original dvbt_tx_demo_8k flow graph from gr-dvbt, the spectrum I generate with 003.008.003-RC1 has a 3dB bandwidth of about ~7.5MHz the same as your uhd_master screen shot. I don't see the truncated bandwidth of your uhd_rc1 screenshot. http://ianbuckley.net/dvbt.jpg
Can you verify please that you have UHD at the current 003.008.003-RC1 tag position git hash 2fe319d9790c7ec0bcdb9582c4fea95f3fd809b9, and that the downloaded FPGA images are from: http://files.ettus.com/binaries/images/uhd-images_003.008.003-rc1.zip

I'll need your exact flow graph if I'm to debug this anymore.

-Ian



On Apr 17, 2015, at 11:48 AM, "Ralph A. Schmid, dk5ras" <ralph at schmid.xxx> wrote:

> I have put it all here, flow graphs and screenshots of the flow graphs:
> 
> http://dk5ras.dyndns.org/tmp/DVB/
> 
> This way we can keep it on the list without sending attachments.
> 
> They were taken from the VM container before all the upgrades were made, but
> I did not change anything when upgrading.
> 
> Ralph.
> 
> 
> 
> -----Original Message-----
> From: Ian Buckley [mailto:ianb at ionconcepts.com] 
> Sent: Friday, April 17, 2015 19:25
> To: Ralph A. Schmid, dk5ras
> Cc: 'Martin Braun'; usrp-users at lists.ettus.com; 'GNU Radio Discussion List'
> Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...
> 
> Great Ralph, thats a big help. Can you send me your exact flow graph used to
> generate these 2 plots off list please. I want to re run this scenario and
> see your exact configuration.
> 
> Thanks
> -Ian
> 
> On Apr 17, 2015, at 10:00 AM, "Ralph A. Schmid, dk5ras" <ralph at schmid.xxx>
> wrote:
> 
>> OK, here we go. The hotel TV was dvb-c only, so I had to do the tests 
>> back at home.
>> 
>> I took my perfectly working Kubuntu 14.04 64 bit VM container together 
>> with my B210, made a copy and updated this one, first I made a git 
>> pull to get latest master, built it, rebuilt gnuradio, rebuilt 
>> gr-dvbt, updated the FPGA images, and everything still was fine. The
> chosen dvb-t bandwidth is 8 MHz.
>> 
>> Then I changed to 003_008_003_rc1, did the same procedure, fired up 
>> grc, and the signal was not decodable both with a dvb-t PC receiver 
>> and with an dvb-x analyzer. The analyzer saw the RF level, but no 
>> data, no constellation, nothing, it looked to him like interference.
>> 
>> When you have a look at the two "uhd" screenshots here 
>> http://dk5ras.dyndns.org/tmp/DVB/ made with my spectrum analyzer then 
>> you will find that RC1 produces a somehow narrower signal, so it 
>> really looks something gets cut at the ends with all the filtering and DSP
> stuff.
>> Adjusting the channel bandwidth in the uhd sink block from 0 to a 
>> sensible value changes nothing.
>> 
>> Btw., the dvb-t2 package behaves identical.
>> 
>> Ralph.
>> 
>> 
>> -----Original Message-----
>> From: Martin Braun [mailto:martin.braun at ettus.com]
>> Sent: Wednesday, April 15, 2015 21:14
>> To: Ralph A. Schmid, dk5ras; usrp-users at lists.ettus.com; 'GNU Radio 
>> Discussion List'
>> Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...
>> 
>> master works, but RC1 does not? Huh, I'm confused now. Can you give 
>> some detail on what's going on, so we can try and reproduce this?
>> 
>> Thanks,
>> Martin
>> 
>> On 15.04.2015 12:52, Ralph A. Schmid, dk5ras wrote:
>>> RC1, master seems to work.
>>> 
>>> Ralph.
>>> 
>>> -----Original Message-----
>>> From: Martin Braun [mailto:martin.braun at ettus.com]
>>> Sent: Wednesday, April 15, 2015 15:44
>>> To: Ralph A. Schmid, dk5ras; usrp-users at lists.ettus.com; 'GNU Radio 
>>> Discussion List'
>>> Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...
>>> 
>>> Thanks, Ralph. Just to clarify: When you say 'New UHD', do you mean 
>>> 3.8.3-RC1, or latest master?
>>> 
>>> Martin
>>> 
>>> On 15.04.2015 08:40, Ralph A. Schmid, dk5ras wrote:
>>>> It is a B210, but as a note, due to the up to now missing FPGA 
>>>> images I used 003.008.003-RC1, not the latest master. Still I had no 
>>>> access to a spectrum and DVB-T analyzer, so I have no idea what is 
>>>> happening, I just can confirm that RF is transmitted, and the 
>>>> receiver doesn't get a picture, while with the snapshot of the same 
>>>> VM before the upgrade
>>> is received without problems.
>>>> I will know more in about three hours.
>>>> 
>>>> Ralph.
>>>> 
>>>>> -----Original Message-----
>>>>> From: Martin Braun [mailto:martin.braun at ettus.com]
>>>>> Sent: Wednesday, April 15, 2015 3:15 PM
>>>>> To: Ralph A. Schmid, dk5ras; usrp-users at lists.ettus.com; 'GNU Radio 
>>>>> Discussion List'
>>>>> Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...
>>>>> 
>>>>> On 15.04.2015 06:20, Ralph A. Schmid, dk5ras wrote:
>>>>>> Hi,
>>>>>> 
>>>>>> Not only OpenBTS is affected, also gr-dvbt/t2 do not work any more 
>>>>>> with latest uhd. A quick check during lunch break showed, the 
>>>>>> produced output is not decodable any more. I will take a closer 
>>>>>> look this evening at home, where I have more and better equipment.
>>>>> 
>>>>> Ralph,
>>>>> 
>>>>> which device is this on?
>>>>> 
>>>>> Thanks,
>>>>> Martin
>>>> 
>>> 
>>> 
>> 
>> 
> 
> 

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