TiredLegs;395799 Wrote: > I'm not an electronics guy, so maybe I'm missing something. These days, > RAM is dirt cheap, so why don't DAC makers just add a gigabyte or two > of memory buffer, and not have to worry about emptying or overflowing > the "bucket" as they reclock the data on the way out? As long as the > buffer is large enough to hold an entire track (or even a CD) worth of > samples, wouldn't that permit a straightforward design that is truly > jitter immune? Such a design could even permit pre-caching the music > into the DAC as fast as the source device could deliver it.
There are simpler ways to fix s/pdif if that's what you want to do. A word clock is all that's needed. What you're describing isn't s/pdif anymore - it's essentially how our products transfer your music, i.e. asynchronously, with flow control and error recovery. It absolutely IS jitter immune because there is no audio clock to speak of. A per track, per album, or whatever fixed unit doesn't make sense. You use a FIFO circular buffer sized to accommodate whatever fluctuations in data flow you expect. http://en.wikipedia.org/wiki/Circular_buffer (In networking terms this is also referred to as a jitter buffer, but they're referring to variance in network latency as opposed to clock noise.) I'm not sure what good a gigabyte of RAM would be - supposing your source clock is faster by 1% (that's a very big error), it would take 1000000000 / 1% / 44100 / 2 / 4 / 60 / 60 == 78 HOURS to overflow. And it would do you no good at all if the sender is slower than the receiver, unless you're willing to wait 78 hours before your music starts. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=50147 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
