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Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay
From: |
Fons Adriaensen |
Subject: |
Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem) |
Date: |
Mon, 14 Nov 2016 20:14:37 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Nov 14, 2016 at 04:59:24PM +0000, Benny Alexandar wrote:
> I have some questions regarding it.
> How many blocks of audio the internal buffer need to store ?
Enough to keep feeding samples to the audio HW until the sink's
work() is called again.
> When does the copy from gr buffer to internal buffer happens ? Is it
> during the audio hardware driver call back or during gr scheduling
> the audio sink ?
When gr calls the sink's work().
> Before copying to the internal buffer the audio block has to be played
> to prevent overwrite of data. In a way it has to do the same check
> what the gr buffers do, space is available to copy etc.
The sink's work() will block until all input data is transferred
to the internal buffer.
> Why not handle this with gr buffer ? Audio sink can query the
> available data in its input queue.
I don't understand what exactly you mean. If you mean that the
internal buffer isn't needed and that the gr buffer can take
its role, that's not going to work.
> I was reading the paper "usingdll.pdf" in that the first figure (fig 1)
> ( The thin (blue) line is the exact mapping we want. Note
> that in this example the real sample frequency is
> slightly lower that the nominal — the thin line
> is lagging the grid as time advances.)
>
> In an ideal case the thin blue line should intersect all the grid points.
> Why the real sample frequency is slightly lower than nominal ?
It's just an example, illustrating what happens in that case.
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)
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), (continued)
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/09
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/09
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/10
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Marcus Müller, 2016/11/10
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/10
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/12
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/12
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/13
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/13
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/14
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem),
Fons Adriaensen <=
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/15
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/15
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Benny Alexandar, 2016/11/06
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/06
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Marcus Müller, 2016/11/06
- Re: [Discuss-gnuradio] Broadcast Receiver Audio Synchronization ( Delay locked loop for the two-clock problem), Fons Adriaensen, 2016/11/06