DeVerm;344567 Wrote: > Sure we can suppose things but it isn't even close to reality. A bad > crystal oscillator (let's suppose this is what's in there as it's > dirt-cheap) is 100 ppm accurate. This translates to 0.001% so that's > 1000 times as good as your assumption and the minute-buffer-time would > actually just be 0.06 seconds instead of 1 minute. These crystals list > at 50 cents a piece. > > Now suppose the manufacturer like us and decides to put in a good > crystal, quality like used in a good watch. It will be around 20 ppm > accurate which translates to 0.0002% so 5000 times as good as assumed > resulting in an error for that 100 minute playback of 0.012 seconds. > These crystals list at $1 a piece > > I talked about oven-controlled crystal oscillators before. They come as > good as 0.01 ppm accurate (!!!) and I can't even type the percentage > without wearing out the "0" key on my keyboard (If I count the zeroes > right on my calculator, it's 1% divided by 10-million!). This top of > the line OCTXCO lists around $100-200. See here: > http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=CW634-ND > > So, even with a 100-minute playback and a 50-cent crystal, there should > be no problem at all. > > cheers, > Nick.
This has absolutely *nothing* to do with jitter. You can not equate absolute frequency and long-term stability to short-term fluctuations. OK, I know a gazillion Chinese websites that pull this nonsense, but it is not relevant to jitter. Absolute frequency errors -can- be caused by loose standards by the folks who grind the crystal. It can also be caused if the guy designing the oscillator not knowing as much about crystals as he has led his boss to believe that he does. Aging can also be caused by this, as damn near every piece in existence uses the same schematic. Without regards to what the drive level is, or should be. Aging within the crystal itself is caused by impurities contained within the holder. Ok, I better shut up before I start getting more hate mail telling me what a horse's butt I am. I already know that. So, spare us the mail. Thanks. Pat -- ar-t http://www.analogresearch-technology.net ------------------------------------------------------------------------ ar-t's Profile: http://forums.slimdevices.com/member.php?userid=13619 View this thread: http://forums.slimdevices.com/showthread.php?t=52817 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
