# Stuttered processing with OsmoSDR and DVB-T Stick **URL:** \ **Category:** GNU Radio\ **Created:** [November 24, 2012, 12:56pm UTC](https://www.ruby-forum.com/t/stuttered-processing-with-osmosdr-and-dvb-t-stick/224749 "2012-11-24T12:56:20Z")\ **Posts on this page:** 3\ **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:** [November 24, 2012, 12:56pm UTC](https://www.ruby-forum.com/t/stuttered-processing-with-osmosdr-and-dvb-t-stick/224749/1 "2012-11-24T12:56:20Z")
Hello, I run gnuradio latest stable installation on a 64bit Ubuntu Installation with Pentium 977 + 8GB RAM. I use the DVB-T Hama Nano DVB-T-Stick which is one of the RTL-Chip derivates. I tried to create a FM-Radio reception which only consists of the OsmoSDR-Srouce, A WBFM Receive PLL and the Audio Sink (see attached png) What I get is a stuttered signal processing of the recepition. I can here the radio signal, but it is interrupted at a rate of approximately 3 Hz. I checked the CPU load but it is well below 100%. Does anyone have an idea what I did wrong? I would appreciate any sort of suggestions. Thanks! Additional experiment: when I make a chain of sine-wave → WBFM-Transmitter → WBFM-Receiver → Audio Sink, with the sample rates as shown in the original fm receiver, there is continuous playback. Therefore I expect that it has something to do with the OsmoSDR, libusb, rtl-driver, rtl-chip. Any suggestions? Regards, # Markus m48/m48+ by Markus Gonser Internet: [http://www.mksg.de](http://www.mksg.de) m48 on the AppStore: [Connecting to the iTunes Store.](http://itunes.com/apps/m48) m48+ on the AppStore: [http://itunes.apple.com/app/m48/id341541461?mt=8](http://itunes.apple.com/app/m48/id341541461?mt=8) E-Mail: removed\_email\_address@domain.invalid ---
**Author:** ![dk3qu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/d2c977/32.png) [@dk3qu](https://www.ruby-forum.com/u/dk3qu)\ **Post date:** [November 24, 2012, 2:34pm UTC](https://www.ruby-forum.com/t/stuttered-processing-with-osmosdr-and-dvb-t-stick/224749/2 "2012-11-24T14:34:29Z")
On 24/11/12 06:55 AM, Markus Gonser wrote: > approximately 3 Hz. I checked the CPU load but it is well below 100%. > > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) > 705.6k is likely not a supported sample rate on the RTLSDR. It’s fairly rare that sample rates on any SDR are exactly multiples of audio rates, so you have to use rational resamplers, or fractional interpolators to match rates. ---
**Author:** ![dk3qu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/d2c977/32.png) [@dk3qu](https://www.ruby-forum.com/u/dk3qu)\ **Post date:** [November 25, 2012, 5:31pm UTC](https://www.ruby-forum.com/t/stuttered-processing-with-osmosdr-and-dvb-t-stick/224749/3 "2012-11-25T17:31:53Z")
Hey Marcus, thank you for your feedback. That must have been it! I also tried the simple\_fm\_rcv exmample on [Rtl-sdr - rtl-sdr - Open Source Mobile Communications](http://sdr.osmocom.org/trac/wiki/rtl-sdr) and it actually works wonderfully. Sorry for this premature queastion. Regards, Markus Am 24.11.2012 um 14:32 schrieb “Marcus D. Leech” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):