# GMSK Transmit **URL:** \ **Category:** GNU Radio\ **Created:** [July 16, 2014, 12:52am UTC](https://www.ruby-forum.com/t/gmsk-transmit/230983 "2014-07-16T00:52:18Z")\ **Posts on this page:** 3\ **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:** [July 16, 2014, 12:52am UTC](https://www.ruby-forum.com/t/gmsk-transmit/230983/1 "2014-07-16T00:52:18Z")
I am working a project where I need to receive bytes via a UDP source, encode as GMSK and transmit via Ettus UHD. My main question is how do I set the bit rate since I really cannot control the UDP source? My receiving radio is expecting 9600 bps. Thank you, Al – ==================== Al Anderson, N0XV Director, IT Services Salish Kootenai College § 406.275.4833 © 406.214.8292 removed\_email\_address@domain.invalid ---
**Author:** ![Al\_Anderson](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/3e96dc/32.png) [@Al\_Anderson](https://www.ruby-forum.com/u/Al_Anderson)\ **Post date:** [July 16, 2014, 1:03am UTC](https://www.ruby-forum.com/t/gmsk-transmit/230983/2 "2014-07-16T01:03:02Z")
Fortunately, the rate is set by the USRP sample rate, not by the rate of the UDP block. -John ---
**Author:** ![Al\_Anderson](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/3e96dc/32.png) [@Al\_Anderson](https://www.ruby-forum.com/u/Al_Anderson)\ **Post date:** [July 16, 2014, 1:07am UTC](https://www.ruby-forum.com/t/gmsk-transmit/230983/3 "2014-07-16T01:07:12Z")
It is dependent on sample rate of graph. You may check this video for an example to transmit 9600 bps GFSK [![](https://img.youtube.com/vi/N1hR6VgWeow/maxresdefault.jpg "grc gfsk example") ](https://www.youtube.com/watch?v=N1hR6VgWeow) In this case, sample rate effectively set by throttle block because of no real hardware: 96000 samples/second GFSK modulator: 10 samples/symbol results in 9600 symbols/second and assuming 1 bit per symbol, 9600 bps. On Wed, Jul 16, 2014 at 9:01 AM, John M.