# New UHD seems to break a lot **URL:** \ **Category:** GNU Radio\ **Created:** [April 15, 2015, 1:22pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564 "2015-04-15T13:22:17Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Post date:** [April 15, 2015, 1:22pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/1 "2015-04-15T13:22:17Z")
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. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 15, 2015, 3:16pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/2 "2015-04-15T15:16:55Z")
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 ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 15, 2015, 3:42pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/3 "2015-04-15T15:42:49Z")
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. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 15, 2015, 3:46pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/4 "2015-04-15T15:46:26Z")
Thanks, Ralph. Just to clarify: When you say ‘New UHD’, do you mean 3.8.3-RC1, or latest master? Martin ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 15, 2015, 7:53pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/5 "2015-04-15T19:53:45Z")
RC1, master seems to work. Ralph. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 15, 2015, 9:16pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/6 "2015-04-15T21:16:29Z")
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 ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 16, 2015, 7:15am UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/7 "2015-04-16T07:15:22Z")
Due to a mistake I lost this copy of the VM yesterday 😕 I try to reproduce the issues this evening, I am traveling, so lots of time in the evening, but no test equipment. Hopefully the hotel TV set will do DVB-T 🙂 Otherwise it will have to wait for the weekend… Ralph. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 17, 2015, 7:02pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/8 "2015-04-17T19:02:37Z")
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/](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. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 17, 2015, 7:26pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/9 "2015-04-17T19:26:48Z")
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 ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 17, 2015, 8:50pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/10 "2015-04-17T20:50:08Z")
I have put it all here, flow graphs and screenshots of the flow graphs: [http://dk5ras.dyndns.org/tmp/DVB/](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. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 18, 2015, 3:46am UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/11 "2015-04-18T03:46:16Z")
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](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](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 ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 18, 2015, 9:26am UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/12 "2015-04-18T09:26:15Z")
Yes, I can confirm hash 2fe3…, and the images were downloaded with the supplied uhd\_image\_downloader, what is configured like this: \_DEFAULT\_BASE\_URL = “[files.ettus.com:/binaries/images/](http://files.ettus.com/binaries/images/)” \_AUTOGEN\_IMAGES\_FILENAME = “uhd-images\_003.008.003-rc1.zip” \_AUTOGEN\_IMAGES\_CHECKSUM = “8522b02386f5fe0bb51baa3ba0001ef0” The GRC filkes are accessible now, the only modifications I made were due to Ron E.’ hints regarding sampling rate, and I added a frequency slider to choose the correct European TV channel without having to know the frequency. Ralph. From: Ian B. [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] Sent: Saturday, April 18, 2015 03:45 To: Ralph A. Schmid, dk5ras Cc: ‘Martin B.’; removed\_email\_address@domain.invalid; ‘GNU Radio D.ion List’ Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot… 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](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](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” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: I have put it all here, flow graphs and screenshots of the flow graphs: [http://dk5ras.dyndns.org/tmp/DVB/](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. ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 20, 2015, 8:07pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/13 "2015-04-20T20:07:02Z")
To close the loop on this thread, 3.8.3-RC1 has a bug in new code that automatically calculates master\_clock\_rates when they are not explicitly stated. This specifically affects B2x0 and E3x0 since they are AD9361 based with a very flexible master\_clock\_rate. In this case Ralph asked for a sample\_rate of 9.142857 MHz and UHD erroneously forced a master\_clock\_rate of 8MHz. An explicit master\_clcok\_rate request (in this case for 9.142857MHz) works around the bug as shown (green without, yellow with): [http://ianbuckley.net/ralph\_spectrum.jpg](http://ianbuckley.net/ralph_spectrum.jpg). The master\_clock\_rate override does print a warning in the UHD log so you can see that this is happening: UHD Warning: The hardware does not support the requested TX sample rate: Target sample rate: 9.142857 MSps Actual sample rate: 8.000000 MSps There is also another bug in RC1 that also prints incorrect warnings. Warnings of this form can currently be ignored until this is fixed should you know that you have actually set sensible sample\_rates: UHD Warning: The requested decimation is odd; the user should expect CIC rolloff. Select an even decimation to ensure that a halfband filter is enabled. decimation = dsp\_rate/samp\_rate → 37 = (9.142857 MHz)/(0.250000 MHz) NOTE: Ralph, your flow graph used a TX gain of 99this is way too high for the signal being driven to the USRP, you were driving the output amp into saturation. -Ian ---
**Author:** ![Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/91b2a8/32.png) [@Ralph\_ASSchmidS\_dk](https://www.ruby-forum.com/u/Ralph_ASSchmidS_dk)\ **Post date:** [April 20, 2015, 9:29pm UTC](https://www.ruby-forum.com/t/new-uhd-seems-to-break-a-lot/241564/14 "2015-04-20T21:29:20Z")
Thanks for all the research - sound reasonable, now I know what is going wrong, great! Regarding the TX gain, I was never able to see any nonlinearity from saturation, the amp seems to be way below the critical input level. The signal is 1a clean, no spurs and no excessive harmonics, no IM. Ralph. From: Ian B. [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] Sent: Monday, April 20, 2015 20:05 To: Ralph A. Schmid, dk5ras Cc: ‘Martin B.’; removed\_email\_address@domain.invalid; ‘GNU Radio D.ion List’ Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot… To close the loop on this thread, 3.8.3-RC1 has a bug in new code that automatically calculates master\_clock\_rates when they are not explicitly stated. This specifically affects B2x0 and E3x0 since they are AD9361 based with a very flexible master\_clock\_rate. In this case Ralph asked for a sample\_rate of 9.142857 MHz and UHD erroneously forced a master\_clock\_rate of 8MHz. An explicit master\_clcok\_rate request (in this case for 9.142857MHz) works around the bug as shown (green without, yellow with): [http://ianbuckley.net/ralph\_spectrum.jpg](http://ianbuckley.net/ralph_spectrum.jpg). The master\_clock\_rate override does print a warning in the UHD log so you can see that this is happening: UHD Warning: ``` The hardware does not support the requested TX sample rate: Target sample rate: 9.142857 MSps Actual sample rate: 8.000000 MSps ``` There is also another bug in RC1 that also prints incorrect warnings. Warnings of this form can currently be ignored until this is fixed should you know that you have actually set sensible sample\_rates: UHD Warning: ``` The requested decimation is odd; the user should expect CIC rolloff. Select an even decimation to ensure that a halfband filter is ``` enabled. ``` decimation = dsp_rate/samp_rate -> 37 = (9.142857 MHz)/(0.250000 ``` MHz) NOTE: Ralph, your flow graph used a TX gain of 99.this is way too high for the signal being driven to the USRP, you were driving the output amp into saturation. -Ian On Apr 18, 2015, at 12:24 AM, “Ralph A. Schmid, dk5ras” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Yes, I can confirm hash 2fe3…, and the images were downloaded with the supplied uhd\_image\_downloader, what is configured like this: \_DEFAULT\_BASE\_URL = " [http://files.ettus.com/binaries/images/](http://files.ettus.com/binaries/images/) [files.ettus.com:/binaries/images/](http://files.ettus.com/binaries/images/)" \_AUTOGEN\_IMAGES\_FILENAME = “uhd-images\_003.008.003-rc1.zip” \_AUTOGEN\_IMAGES\_CHECKSUM = “8522b02386f5fe0bb51baa3ba0001ef0” The GRC filkes are accessible now, the only modifications I made were due to Ron E.’ hints regarding sampling rate, and I added a frequency slider to choose the correct European TV channel without having to know the frequency. Ralph. From: Ian B. [mailto:ianb@ [http://ionconcepts.com](http://ionconcepts.com) [ionconcepts.com](http://ionconcepts.com)] Sent: Saturday, April 18, 2015 03:45 To: Ralph A. Schmid, dk5ras Cc: ‘Martin B.’; [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) removed\_email\_address@domain.invalid; ‘GNU Radio D.ion List’ Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot… 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](http://ianbuckley.net/dvbt.jpg) [![](http://ianbuckley.net/dvbt.jpg) ](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](http://files.ettus.com/binaries/images/uhd-images_003.008.003-rc1.zip) [http://files.ettus.com/binaries/images/uhd-images\_003.008.003-rc1.zip](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” \< [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) removed\_email\_address@domain.invalid\> wrote: I have put it all here, flow graphs and screenshots of the flow graphs: [http://dk5ras.dyndns.org/tmp/DVB/](http://dk5ras.dyndns.org/tmp/DVB/) [http://dk5ras.dyndns.org/tmp/DVB/](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.