Thanks Marcus, It sounds like a good idea but I think I haven't explained my flow graph well enough. This a simplification of what I've got.
[image: Inline images 1] I've taken away one of the cards, filters and others. Can I still use your approach using "streams to vector" -> "vector to streams" in this situation? Thanks, Murray On 13 January 2016 at 10:10, Marcus Müller <[email protected]> wrote: > Well, that could well be; at 96kHz, 1s after a day is a drift of > [image: $\frac{\SI{1}{\second}}{24\cdot 60 \cdot > 60\si{\second}}=11.57\,\mathrm{ppm}$] > which would be a relatively good value for soundcard oscillators. > > For drifts that small, you probably won't be able to correct this from > signal. > > I'd say, since you can live with dropping samples, do the following: > > source 1 -> -> > ... ->streams to vector -> vector to streams -> > source N -> -> > > > that enforces sample-synchronity. You then set a maximum size for the > output buffers of the source blocks, if you'd rather lose few samples then > seeing a growing delay and then lose a bigger bunch of samples. > > Best regards, > Marcus > > > On 01/13/2016 08:30 AM, Murray Thomson wrote: > > Hi, > > I'm using three audio cards in my flow graph. The internal and a USB audio > cards run at 96 kHz and I use a virtual audio card with 5 subdevices > loading the snd_aloop kernel module that runs at 48 kHz. > > I've noticed that after some days of running there seems to be a delay > (around 1 second) processing the signal. > > I was wondering if this could be due to the differences in the clocks of > the audio cards. Is there a way to correct these differences? I can afford > losing data every now and again, but an increasing delay it's a problem for > me. > > Thanks, > Murray > > > _______________________________________________ > Discuss-gnuradio mailing > [email protected]https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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