So I recently got a new toy - a Lecroy 64Xi 10GS/s scope, which is vastly more capable of jitter analysis than the old time interval counter I had been using before. It is also able to analyze the s/pdif signal directly, using a software PLL to recover the clock in much the same way that a digital interface receiver chip would.
For these tests, the Squeezebox was connected to our DHL 75ohm cable (which are quite good BTW), and the other end to an RCA->BNC adaptor, then a BNC "T" directly into the scope input, with a 75ohm BNC terminator cap on the other end of the "T". So the scope is measuring practically the same thing that an s/pdif receiver in a DAC would receive. I tested both SB2 and SB3, since SB3 uses a linear reg for its internal logic rail instead of the switcher in SB2. The test was done using Lecroy's "Time interval error" measurement, which tracks the incoming data and compares the edges to the ideal recovered clock. These measurements then go into a histogram (2500 values in 1000 bins) for statistical analysis. The setup is very reliable and the measurements were found to be repeatable. The Linear supply used for these tests was a protek 3003B. So here are the results (picoseconds): sigma RMS pk-pk SB2 Linear 61 62 460 SB2 SMPS 64 69 455 SB3 Linear 72 82 491 SB3 SMPS 69 71 459 I don't think any of the differences here are enough to conclude any advantage of one ps over the other, or any difference between SB2 and SB3. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=24392 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
