# TX Gain parameter in uhd\_siggen\_gui **URL:** \ **Category:** GNU Radio\ **Created:** [September 8, 2014, 4:52pm UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942 "2014-09-08T16:52:50Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [September 8, 2014, 4:52pm UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942/1 "2014-09-08T16:52:50Z")
Hello everyone, Im trying to set the TX Gain of USRP device using the following command while transmitting using uhd\_siggen\_gui tool: ./uhd\_siggen\_gui --sine -g \ -f 1013M --amplitude=1.0 -A TX/RX -v If I set the TX\_Gain to non integer or non 0.5 fractional values, it is getting set to nearest integer or 0.5 fractional values. For example, if I set TX\_Gain to 22.6, it will be set to 22.5 as shown in gui Similary, setting TX\_Gain to 22.1 will set it to 22, 19.9 will set it to 19.5 etc But I can set the TX\_Gain properly using the gui slider. Any idea on how to set it properly using command line? Thanks – View this message in context: [http://gnuradio.4.n7.nabble.com/TX-Gain-parameter-in-uhd-siggen-gui-tp50321.html](http://gnuradio.4.n7.nabble.com/TX-Gain-parameter-in-uhd-siggen-gui-tp50321.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![zealdeal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/ecb155/32.png) [@zealdeal](https://www.ruby-forum.com/u/zealdeal)\ **Post date:** [September 8, 2014, 5:05pm UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942/2 "2014-09-08T17:05:11Z")
The total gain setting range, and gain step size are set by the hardware. In most cases, the step size is 0.5dB. On 2014-09-08 10:50, zealdeal wrote: > ## For example, if I set TX\_Gain to 22.6, it will be set to 22.5 as shown in > > View this message in context: > [http://gnuradio.4.n7.nabble.com/TX-Gain-parameter-in-uhd-siggen-gui-tp50321.html](http://gnuradio.4.n7.nabble.com/TX-Gain-parameter-in-uhd-siggen-gui-tp50321.html) > [1] > Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). > > * * * > > Discuss-gnuradio mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) [2] Links: ---
**Author:** ![zealdeal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/ecb155/32.png) [@zealdeal](https://www.ruby-forum.com/u/zealdeal)\ **Post date:** [September 8, 2014, 5:30pm UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942/3 "2014-09-08T17:30:26Z")
In other words, it’s the slider that’s buggy, not the gain setting. M ---
**Author:** ![zealdeal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/ecb155/32.png) [@zealdeal](https://www.ruby-forum.com/u/zealdeal)\ **Post date:** [September 9, 2014, 5:15am UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942/4 "2014-09-09T05:15:19Z")
Thanks for the info. Can anybody please confirm whether the step size limit of 0.5 dB is valid for USRP N200? – View this message in context: [http://gnuradio.4.n7.nabble.com/TX-Gain-parameter-in-uhd-siggen-gui-tp50321p50334.html](http://gnuradio.4.n7.nabble.com/TX-Gain-parameter-in-uhd-siggen-gui-tp50321p50334.html) Sent from the GnuRadio mailing list archive at [Nabble.com](http://Nabble.com). ---
**Author:** ![zealdeal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/ecb155/32.png) [@zealdeal](https://www.ruby-forum.com/u/zealdeal)\ **Post date:** [September 9, 2014, 5:20am UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942/5 "2014-09-09T05:20:15Z")
On 09/08/2014 11:13 PM, zealdeal wrote: > Thanks for the info. Can anybody please confirm whether the step size limit > of 0.5 dB is valid for USRP N200? It’s not the underlying motherboard, it’s the daughter-cards. I think all of WBX, SBX and CBX use a step attenuator with 0.5dB step size. Others, I’m not sure about. Generally, the “analog stuff” is on the daughtercards, and gain-setting is definitely “analog stuff”. If you need fine-grained control over output power, you can vary the magnitude of your baseband signals, where you have much-finer control available. Although, I have to admit that, except for certain laboratory experiments, power-control beyond 0.5dB granularity is of very little use in any practical sense. ---
**Author:** ![zealdeal](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/ecb155/32.png) [@zealdeal](https://www.ruby-forum.com/u/zealdeal)\ **Post date:** [September 9, 2014, 3:30pm UTC](https://www.ruby-forum.com/t/tx-gain-parameter-in-uhd-siggen-gui/231942/6 "2014-09-09T15:30:50Z")
On Mon, Sep 8, 2014 at 11:13 PM, zealdeal [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Thanks for the info. Can anybody please confirm whether the step size limit > of 0.5 dB is valid for USRP N200? Use their tool uhd\_usrp\_probe to find the specifics of your USRP and daughterboards. Tom