# How to set a master clock rate on USRP B200 **URL:** \ **Category:** GNU Radio\ **Created:** [May 23, 2014, 6:24pm UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950 "2014-05-23T18:24:57Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jason\_sam](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7993a0/32.png) [@jason\_sam](https://www.ruby-forum.com/u/jason_sam)\ **Post date:** [May 23, 2014, 6:24pm UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/1 "2014-05-23T18:24:57Z")
Hello All Gnu Radio user, To use a 2 TX, I want to change a clock rate to an accepted one, under 30.72 MHz. I use the API with uhd\_usrp\_probe and it works only for this command. Can you give me the idea or python code to use this argument parameter with a python flowgraph? –args="master\_clock\_rate=28"Thanks. ---
**Author:** ![raf\_raf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@raf\_raf](https://www.ruby-forum.com/u/raf_raf)\ **Post date:** [May 26, 2014, 5:40am UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/2 "2014-05-26T05:40:43Z")
“device args” parameter is not in the UHD USRP source/sink block?There is only ‘Device addr’ ---
**Author:** ![raf\_raf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@raf\_raf](https://www.ruby-forum.com/u/raf_raf)\ **Post date:** [May 23, 2014, 6:40pm UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/3 "2014-05-23T18:40:23Z")
On 05/23/2014 12:23 PM, raf raf wrote: > * * * > > 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) > In GRC, where it has a “device args” parameter, that’s wher this > master\_clock\_rate=28e6 should go. I assume you meant 28e6, rather than 1. Everything is in Hz, and there’s no way the B200 can go down to a clock rate of 28Hz. ---
**Author:** ![raf\_raf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@raf\_raf](https://www.ruby-forum.com/u/raf_raf)\ **Post date:** [May 26, 2014, 8:44am UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/4 "2014-05-26T08:44:36Z")
There is a device args field in the current version of GNU Radio, so this might be where the confusion comes from. ---
**Author:** ![raf\_raf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@raf\_raf](https://www.ruby-forum.com/u/raf_raf)\ **Post date:** [May 26, 2014, 5:42am UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/5 "2014-05-26T05:42:34Z")
On 05/25/2014 11:39 PM, jason sam wrote: > “device args” parameter is not in the UHD USRP source/sink block?There > is only ‘Device addr’ Sorry, I meant Device Addr ---
**Author:** ![raf\_raf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@raf\_raf](https://www.ruby-forum.com/u/raf_raf)\ **Post date:** [May 26, 2014, 10:05am UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/6 "2014-05-26T10:05:16Z")
On 26.05.2014 08:43, Marcus M. wrote: > There is a device args field in the current version of GNU Radio, so > this might be where the confusion comes from. Yes, for the record: In UHD, ‘args’ and ‘addr’ (address) are the same thing. So, this is an addr: “type=b200,master\_clock\_rate=28e6”. Clearly, this is _both_ an address and an argument, which is where confusion can come from. - Martin ---
**Author:** ![raf\_raf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/6bbea6/32.png) [@raf\_raf](https://www.ruby-forum.com/u/raf_raf)\ **Post date:** [May 26, 2014, 10:28am UTC](https://www.ruby-forum.com/t/how-to-set-a-master-clock-rate-on-usrp-b200/229950/7 "2014-05-26T10:28:03Z")
Thank you, In GRC, I changed Clock Rate (Hz) by giving a value of 28e6 and it works now. Date: Sun, 25 May 2014 23:41:01 -0400 From: removed\_email\_address@domain.invalid To: removed\_email\_address@domain.invalid CC: removed\_email\_address@domain.invalid; removed\_email\_address@domain.invalid Subject: Re: [Discuss-gnuradio] How to set a master clock rate on USRP B200 ``` On 05/25/2014 11:39 PM, jason sam wrote: "device args" parameter is not in the UHD USRP source/sink block?There is only 'Device addr' Sorry, I meant Device Addr On Fri, May 23, 2014 at 9:39 PM, Marcus D. Leech wrote: On 05/23/2014 12:23 PM, raf raf wrote: Hello All Gnu Radio user, To use a 2 TX, I want to change a clock rate to an accepted one, under 30.72 MHz. I use the API with uhd_usrp_probe and it works only for this command. Can you give me the idea or python code to use this argument parameter with a python flowgraph? --args="master_clock_rate=28" Thanks. ``` * * * Discuss-gnuradio mailing list removed\_email\_address@domain.invalid [https://lists.gnu.org/mailman/listinfo/discuss-gnuradio](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) ``` In GRC, where it has a "device args" parameter, that's wher this master_clock_rate=28e6 should go. I assume you meant 28e6, rather than 28. Everything is in Hz, and there's no way the B200 can go down to a clock rate of 28Hz. -- ``` Marcus L. Principal Investigator Shirleys Bay Radio Astronomy Consortium > **[Live Draw HK Tercepat | Result HK | HK Pools | Live HK | HK Prize Hari Ini](https://www.sbrac.org/)** > > Temukan live draw hk tercepat melalui halaman hk pools yang resmi dan dapatkan result hk prize melalui live hk secara langsung di situs kami. ``` _______________________________________________ Discuss-gnuradio mailing list removed_email_address@domain.invalid https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ```