Please find the attached block diagram of how the control loop is placed in the whole system.
In the figure the first block is the RF IQ acquisition block which samples the RF samples and put a timestamp. It is then passed on to channel and audio decoder and finally reaches the audio sink. Audio sink does the audio playback on fragments of audio. The audio control loop module has two inputs and one output. The inputs are for sending the timestamp of write side and read side. In this case the write side is RF capture and read is from audio sink. Note these two time stamps are coming from different clock, the RF capture uses PC CPU clock where as the audio sink has sound card clock. The output of audio control loop is used to control the re sampler which sits in between audio decoder and audio sink. AudCtrlLoop.JPG <http://linux-audio.4202.n7.nabble.com/file/t2646/AudCtrlLoop.JPG> -ben Fons Adriaensen-3 wrote > On Sat, Sep 16, 2017 at 10:17:04PM -0700, benravin wrote: > >> I'm facing a timing jitter which happens periodically due to some >> interrupt, >> which is causing the task to be delayed. Since this happens periodically, >> it >> is indeed a slow varying timing jitter, for example every 400ms, the >> timing >> deviation is in the order of few ms ( 4-6ms). This is not getting >> filtered >> out by DLL, and results in a slow varying oscillations which never dies. >> >> Any way to identify and limit these timing jitters and not to take any >> action on drift correction by DLL ? > > It's impossible to say anything about this if you don't provide > numbers. How big is the resulting resampling ratio variation ? > > If a few ms jitter leads to anything perceptible then your DLL > and/or resampling control loop are not dimensioned correctly, > or there is another basic problem with your design. > > Ciao, > > -- > FA > > A world of exhaustive, reliable metadata would be an utopia. > It's also a pipe-dream, founded on self-delusion, nerd hubris > and hysterically inflated market opportunities. (Cory Doctorow) > > _______________________________________________ > Linux-audio-dev mailing list > Linux-audio-dev@.linuxaudio > https://lists.linuxaudio.org/listinfo/linux-audio-dev ----- -ben -- Sent from: http://linux-audio.4202.n7.nabble.com/linux-audio-dev-f58952.html _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org https://lists.linuxaudio.org/listinfo/linux-audio-dev
