Hello, I have an issue where I tune both the TX and RX side of a UBX40 card in an X310 to the same frequency and find that the transmitted signal and what is received are not coherent.  I am using an external 10MHz reference and have tried the documented suggestions. at 150MHz it is coherent. at 155MHz it is NOT coherent. I have tried setting the dboard_clock_rate to 20MHz.  This made the problem appear at 150MHz as well.  I've tried integer_n tuning. I have verified that the ref_lock and lo_lock are both true. Any suggestions? Mike

Can you elaborate on what "not coherent" means to you – the relative phase should be constant after each tune, but if you don't tune simultaneously, i.e. with timed commands, random at each tune. Best regards, Marcus On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users wrote: > Hello, > > > I have an issue where I tune both the TX and RX side of a UBX40 card > in > an X310 to the same frequency and find that the transmitted signal > and > what is received are not coherent. I am using an external 10MHz > reference and have tried the documented suggestions. > > at 150MHz it is coherent. > > at 155MHz it is NOT coherent. > > > I have tried setting the dboard_clock_rate to 20MHz. This made the > problem appear at 150MHz as well. I've tried integer_n tuning. > > I have verified that the ref_lock and lo_lock are both true. > > > Any suggestions? > > > Mike > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems. Mike Sent from my iPhone On Mar 24, 2019, at 4:28 AM, Marcus Müller <marcus.mueller@ettus.com> wrote: Can you elaborate on what "not coherent" means to you – the relative phase should be constant after each tune, but if you don't tune simultaneously, i.e. with timed commands, random at each tune. Best regards, Marcus On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users wrote: > Hello, > > > I have an issue where I tune both the TX and RX side of a UBX40 card > in > an X310 to the same frequency and find that the transmitted signal > and > what is received are not coherent. I am using an external 10MHz > reference and have tried the documented suggestions. > > at 150MHz it is coherent. > > at 155MHz it is NOT coherent. > > > I have tried setting the dboard_clock_rate to 20MHz. This made the > problem appear at 150MHz as well. I've tried integer_n tuning. > > I have verified that the ref_lock and lo_lock are both true. > > > Any suggestions? > > > Mike > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

I can fully understand that! You don't happen to have an estimate for that frequency offset's magnitude? Is it always the same drift? I'm trying to narrow down analog vs numerical accuracy issues here. Best regards, Marcus On Sun, 2019-03-24 at 18:39 +0000, Freedman, Michael - 1008 - MITLL wrote: > It is not just a phase offset. It is a frequency offset. The phase > drifts between the two. I can tolerate a phase offset at startup. A > freq offset however is causing problems. > > Mike > > Sent from my iPhone > > On Mar 24, 2019, at 4:28 AM, Marcus Müller <marcus.mueller@ettus.com> > wrote: > > Can you elaborate on what "not coherent" means to you – the relative > phase should be constant after each tune, but if you don't tune > simultaneously, i.e. with timed commands, random at each tune. > > Best regards, > Marcus > On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users > wrote: > > Hello, > > > > > > I have an issue where I tune both the TX and RX side of a UBX40 > > card > > in > > an X310 to the same frequency and find that the transmitted signal > > and > > what is received are not coherent. I am using an external 10MHz > > reference and have tried the documented suggestions. > > > > at 150MHz it is coherent. > > > > at 155MHz it is NOT coherent. > > > > > > I have tried setting the dboard_clock_rate to 20MHz. This made > > the > > problem appear at 150MHz as well. I've tried integer_n tuning. > > > > I have verified that the ref_lock and lo_lock are both true. > > > > > > Any suggestions? > > > > > > Mike > > > > > > _______________________________________________ > > USRP-users mailing list > > USRP-users@lists.ettus.com > > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

On 03/24/2019 02:39 PM, Freedman, Michael - 1008 - MITLL via USRP-users wrote: > It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems. > > Mike > > Sent from my iPhone > > On Mar 24, 2019, at 4:28 AM, Marcus Müller <marcus.mueller@ettus.com> wrote: > > Can you elaborate on what "not coherent" means to you – the relative > phase should be constant after each tune, but if you don't tune > simultaneously, i.e. with timed commands, random at each tune. > > Best regards, > Marcus Also, what version of UHD? What hardware rev of UBX cards? > On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users > wrote: >> Hello, >> >> >> I have an issue where I tune both the TX and RX side of a UBX40 card >> in >> an X310 to the same frequency and find that the transmitted signal >> and >> what is received are not coherent. I am using an external 10MHz >> reference and have tried the documented suggestions. >> >> at 150MHz it is coherent. >> >> at 155MHz it is NOT coherent. >> >> >> I have tried setting the dboard_clock_rate to 20MHz. This made the >> problem appear at 150MHz as well. I've tried integer_n tuning. >> >> I have verified that the ref_lock and lo_lock are both true. >> >> >> Any suggestions? >> >> >> Mike >> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Marcus, In this setup I have 6 UBX-160 v2 and 6 UBX-40 v2.    The USRPs are all X310 Rev 11, Rev_compat 7.   I have tried 3.13.1 as well as 3.14-rc3. Thanks!    Mike On 03/24/2019 03:23 PM, Marcus D. Leech via USRP-users wrote: > On 03/24/2019 02:39 PM, Freedman, Michael - 1008 - MITLL via > USRP-users wrote: >> It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems. >> >> Mike >> >> Sent from my iPhone >> >> On Mar 24, 2019, at 4:28 AM, Marcus Müller<marcus.mueller@ettus.com> wrote: >> >> Can you elaborate on what "not coherent" means to you – the relative >> phase should be constant after each tune, but if you don't tune >> simultaneously, i.e. with timed commands, random at each tune. >> >> Best regards, >> Marcus > Also, what version of UHD?  What hardware rev of UBX cards? > > >> On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users >> wrote: >>> Hello, >>> >>> >>> I have an issue where I tune both the TX and RX side of a UBX40 card >>> in >>> an X310 to the same frequency and find that the transmitted signal >>> and >>> what is received are not coherent. I am using an external 10MHz >>> reference and have tried the documented suggestions. >>> >>> at 150MHz it is coherent. >>> >>> at 155MHz it is NOT coherent. >>> >>> >>> I have tried setting the dboard_clock_rate to 20MHz. This made the >>> problem appear at 150MHz as well. I've tried integer_n tuning. >>> >>> I have verified that the ref_lock and lo_lock are both true. >>> >>> >>> Any suggestions? >>> >>> >>> Mike >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Marcus, Thanks for engaging in this.  I will have frequency deltas for you first thing this afternoon. Mike On 03/24/2019 03:07 PM, Marcus Müller wrote: > I can fully understand that! You don't happen to have an estimate for > that frequency offset's magnitude? Is it always the same drift? I'm > trying to narrow down analog vs numerical accuracy issues here. > > Best regards, > Marcus > On Sun, 2019-03-24 at 18:39 +0000, Freedman, Michael - 1008 - MITLL > wrote: >> It is not just a phase offset. It is a frequency offset. The phase >> drifts between the two. I can tolerate a phase offset at startup. A >> freq offset however is causing problems. >> >> Mike >> >> Sent from my iPhone >> >> On Mar 24, 2019, at 4:28 AM, Marcus Müller <marcus.mueller@ettus.com> >> wrote: >> >> Can you elaborate on what "not coherent" means to you – the relative >> phase should be constant after each tune, but if you don't tune >> simultaneously, i.e. with timed commands, random at each tune. >> >> Best regards, >> Marcus >> On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users >> wrote: >>> Hello, >>> >>> >>> I have an issue where I tune both the TX and RX side of a UBX40 >>> card >>> in >>> an X310 to the same frequency and find that the transmitted signal >>> and >>> what is received are not coherent. I am using an external 10MHz >>> reference and have tried the documented suggestions. >>> >>> at 150MHz it is coherent. >>> >>> at 155MHz it is NOT coherent. >>> >>> >>> I have tried setting the dboard_clock_rate to 20MHz. This made >>> the >>> problem appear at 150MHz as well. I've tried integer_n tuning. >>> >>> I have verified that the ref_lock and lo_lock are both true. >>> >>> >>> Any suggestions? >>> >>> >>> Mike >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Hello, Do you have any suggestions as to how to measure the frequency delta between the transmit channel and the receive channel? As I sat down to do this, I realized I have no real way to do that. Mike On 03/24/2019 03:23 PM, Marcus D. Leech via USRP-users wrote: > On 03/24/2019 02:39 PM, Freedman, Michael - 1008 - MITLL via > USRP-users wrote: >> It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems. >> >> Mike >> >> Sent from my iPhone >> >> On Mar 24, 2019, at 4:28 AM, Marcus Müller<marcus.mueller@ettus.com> wrote: >> >> Can you elaborate on what "not coherent" means to you – the relative >> phase should be constant after each tune, but if you don't tune >> simultaneously, i.e. with timed commands, random at each tune. >> >> Best regards, >> Marcus > Also, what version of UHD?  What hardware rev of UBX cards? > > >> On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users >> wrote: >>> Hello, >>> >>> >>> I have an issue where I tune both the TX and RX side of a UBX40 card >>> in >>> an X310 to the same frequency and find that the transmitted signal >>> and >>> what is received are not coherent. I am using an external 10MHz >>> reference and have tried the documented suggestions. >>> >>> at 150MHz it is coherent. >>> >>> at 155MHz it is NOT coherent. >>> >>> >>> I have tried setting the dboard_clock_rate to 20MHz. This made the >>> problem appear at 150MHz as well. I've tried integer_n tuning. >>> >>> I have verified that the ref_lock and lo_lock are both true. >>> >>> >>> Any suggestions? >>> >>> >>> Mike >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Well, according to your description, you could transmit a carrier from TX to RX (through an attenuator) with both sides set to the same frequency. Your received signal should look like a sine wave at the frequency of the offset. On Mon, Mar 25, 2019 at 9:16 AM Michael R. Freedman via USRP-users < usrp-users@lists.ettus.com> wrote: > Hello, > > Do you have any suggestions as to how to measure the frequency delta > between the transmit channel and the receive channel? > > As I sat down to do this, I realized I have no real way to do that. > > > Mike > > > > > > On 03/24/2019 03:23 PM, Marcus D. Leech via USRP-users wrote: > > On 03/24/2019 02:39 PM, Freedman, Michael - 1008 - MITLL via USRP-users > wrote: > > It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems. > > Mike > > Sent from my iPhone > > On Mar 24, 2019, at 4:28 AM, Marcus Müller <marcus.mueller@ettus.com> <marcus.mueller@ettus.com> wrote: > > Can you elaborate on what "not coherent" means to you – the relative > phase should be constant after each tune, but if you don't tune > simultaneously, i.e. with timed commands, random at each tune. > > Best regards, > Marcus > > Also, what version of UHD? What hardware rev of UBX cards? > > > On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users > wrote: > > Hello, > > > I have an issue where I tune both the TX and RX side of a UBX40 card > in > an X310 to the same frequency and find that the transmitted signal > and > what is received are not coherent. I am using an external 10MHz > reference and have tried the documented suggestions. > > at 150MHz it is coherent. > > at 155MHz it is NOT coherent. > > > I have tried setting the dboard_clock_rate to 20MHz. This made the > problem appear at 150MHz as well. I've tried integer_n tuning. > > I have verified that the ref_lock and lo_lock are both true. > > > Any suggestions? > > > Mike > > > _______________________________________________ > USRP-users mailing listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > _______________________________________________ > USRP-users mailing listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > > > _______________________________________________ > USRP-users mailing listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >

 Hello,

 Do you have any suggestions as to how to measure the frequency
 delta between the transmit channel and the receive channel?

 As I sat down to do this, I realized I have no real way to do that.


 Mike





 On 03/24/2019 03:23 PM, Marcus D. Leech via USRP-users wrote:

 On 03/24/2019 02:39 PM, Freedman, Michael - 1008 - MITLL via
 USRP-users wrote:

 It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems.

 Mike

 Sent from my iPhone

 On Mar 24, 2019, at 4:28 AM, Marcus Müller<marcus.mueller@ettus.com> <mailto:marcus.mueller@ettus.com>  wrote:

 Can you elaborate on what "not coherent" means to you – the relative
 phase should be constant after each tune, but if you don't tune
 simultaneously, i.e. with timed commands, random at each tune.

 Best regards,
 Marcus

 Also, what version of UHD?  What hardware rev of UBX cards?

 On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users
 wrote:

 Hello,


 I have an issue where I tune both the TX and RX side of a UBX40 card
 in
 an X310 to the same frequency and find that the transmitted signal
 and
 what is received are not coherent.  I am using an external 10MHz
 reference and have tried the documented suggestions.

 at 150MHz it is coherent.

 at 155MHz it is NOT coherent.


 I have tried setting the dboard_clock_rate to 20MHz.  This made the
 problem appear at 150MHz as well.  I've tried integer_n tuning.

 I have verified that the ref_lock and lo_lock are both true.


 Any suggestions?


 Mike


 _______________________________________________
 USRP-users mailing list
 USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
 http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

 _______________________________________________
 USRP-users mailing list
 USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
 http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

 _______________________________________________
 USRP-users mailing list
 USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
 http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

 _______________________________________________
 USRP-users mailing list
 USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
 http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com

Marcus,    190Hz is what we calculated.  I have attached a text file with the data we used.  This is a single UBX40 tuned to 155MHz sampling at 2MHz. Mike On 03/25/2019 12:34 PM, Nick Foster wrote: > Well, according to your description, you could transmit a carrier from > TX to RX (through an attenuator) with both sides set to the same > frequency. Your received signal should look like a sine wave at the > frequency of the offset. > > On Mon, Mar 25, 2019 at 9:16 AM Michael R. Freedman via USRP-users > <usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>> wrote: > > Hello, > > Do you have any suggestions as to how to measure the frequency > delta between the transmit channel and the receive channel? > > As I sat down to do this, I realized I have no real way to do that. > > > Mike > > > > > > On 03/24/2019 03:23 PM, Marcus D. Leech via USRP-users wrote: >> On 03/24/2019 02:39 PM, Freedman, Michael - 1008 - MITLL via >> USRP-users wrote: >>> It is not just a phase offset. It is a frequency offset. The phase drifts between the two. I can tolerate a phase offset at startup. A freq offset however is causing problems. >>> >>> Mike >>> >>> Sent from my iPhone >>> >>> On Mar 24, 2019, at 4:28 AM, Marcus Müller<marcus.mueller@ettus.com> <mailto:marcus.mueller@ettus.com> wrote: >>> >>> Can you elaborate on what "not coherent" means to you – the relative >>> phase should be constant after each tune, but if you don't tune >>> simultaneously, i.e. with timed commands, random at each tune. >>> >>> Best regards, >>> Marcus >> Also, what version of UHD?  What hardware rev of UBX cards? >> >> >>> On Sat, 2019-03-23 at 17:06 -0400, Michael R. Freedman via USRP-users >>> wrote: >>>> Hello, >>>> >>>> >>>> I have an issue where I tune both the TX and RX side of a UBX40 card >>>> in >>>> an X310 to the same frequency and find that the transmitted signal >>>> and >>>> what is received are not coherent. I am using an external 10MHz >>>> reference and have tried the documented suggestions. >>>> >>>> at 150MHz it is coherent. >>>> >>>> at 155MHz it is NOT coherent. >>>> >>>> >>>> I have tried setting the dboard_clock_rate to 20MHz. This made the >>>> problem appear at 150MHz as well. I've tried integer_n tuning. >>>> >>>> I have verified that the ref_lock and lo_lock are both true. >>>> >>>> >>>> Any suggestions? >>>> >>>> >>>> Mike >>>> >>>> >>>> _______________________________________________ >>>> USRP-users mailing list >>>> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com> >>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com> >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> >> >> >> _______________________________________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com> >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >