# Re: No Digital Modulation Working **URL:** \ **Category:** GNU Radio\ **Created:** [October 24, 2012, 3:45am UTC](https://www.ruby-forum.com/t/re-no-digital-modulation-working/223934 "2012-10-24T03:45:50Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![aris](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/258eb7/32.png) [@aris](https://www.ruby-forum.com/u/aris)\ **Post date:** [October 24, 2012, 3:45am UTC](https://www.ruby-forum.com/t/re-no-digital-modulation-working/223934/1 "2012-10-24T03:45:50Z")
On 10/22/2012 03:03 PM, Ahmed Z. wrote: > attached file or provide me with any transceiver using any digital > modulation which should work on latest gnuradio with USRP N210 that > would really be a great help. I really appreciate your help. > Regards. Ahmed. Hi, If things are working fine for FM modulation,then it’s surely due to LO offset between Tx & Rx. I hope you know on how to correct LO offset. Sumit: If possible, could you please post some videos and tutorials on LO Offset Correction. ---
**Author:** ![senthil\_murugan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/53a042/32.png) [@senthil\_murugan](https://www.ruby-forum.com/u/senthil_murugan)\ **Post date:** [October 24, 2012, 4:59am UTC](https://www.ruby-forum.com/t/re-no-digital-modulation-working/223934/2 "2012-10-24T04:59:26Z")
Yeah …Done already – View this message in context: [http://gnuradio.4.n7.nabble.com/No-Digital-Modulation-Working-tp38097p38129.html](http://gnuradio.4.n7.nabble.com/No-Digital-Modulation-Working-tp38097p38129.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![senthil\_murugan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/53a042/32.png) [@senthil\_murugan](https://www.ruby-forum.com/u/senthil_murugan)\ **Post date:** [October 24, 2012, 5:45pm UTC](https://www.ruby-forum.com/t/re-no-digital-modulation-working/223934/3 "2012-10-24T17:45:00Z")
Apart from what everyone said, what I can see from your attached file is that you are multiplying with 5000 before sending to USRP sink, isn’t it? There is possibly a clipping issue here. Also in the receiver side, you should remove the throttle. Throttle is needed only when there is no hardware involved. If any hardware (such as USRP, audio source/sink) is involved in your flowgraph you don’t need throttle. On Tue, Oct 23, 2012 at 10:58 PM, sumitstop \ **Author:** ![senthil\_murugan](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/53a042/32.png) [@senthil\_murugan](https://www.ruby-forum.com/u/senthil_murugan)\ **Post date:** [October 24, 2012, 6:18pm UTC](https://www.ruby-forum.com/t/re-no-digital-modulation-working/223934/4 "2012-10-24T18:18:18Z") Thanks Sakib, the issue was solved when I changed the multiplying constant to 100 mili. They were not communicating due to clipping. Regards. Ahmed. * * * From: Sakib C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) To: removed\_email\_address@domain.invalid Cc: removed\_email\_address@domain.invalid Sent: Wednesday, October 24, 2012 8:43 AM Subject: Re: [Discuss-gnuradio] No Digital Modulation Working Apart from what everyone said, what I can see from your attached file is that you are multiplying with 5000 before sending to USRP sink, isn’t it? There is possibly a clipping issue here. Also in the receiver side, you should remove the throttle. Throttle is needed only when there is no hardware involved. If any hardware (such as USRP, audio source/sink) is involved in your flowgraph you don’t need throttle. On Tue, Oct 23, 2012 at 10:58 PM, sumitstop [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Yeah …Done already