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A U D I O P H I L L E O 1 & 2
Specifications
Jitter
2.5 ps RMS phase jitter integrated from 10 Hz to 100 kHz. This is
measured using a TSC 5120A phase noise analyzer.
8 ps RMS phase jitter integrated from 1 Hz to 100 kHz. This is measured
using a TSC 5120A phase noise analyzer.
< 5 ps RMS period jitter (< 15 ps peak-peak) This is measured using a
WaveCrest DTS with a sample size of 8000.
Because we were unable to use the off-the-shelf SPDIF testers to test our devices, we
came up with the following technique for obtaining measurements:
We used the TSC 5120A phase noise analyzer to generate phase noise plots from 1Hz
to 100Khz. This tester is designed to measure clocks, not SPDIF signals. In order to
use the 5120A we had to generate periodic clock signals instead of the BMC encoded
SPDIF signals. Fortunately we generate all our signaling in software so in addition to
outputting audio, our SPDIF output stage can output a clock signal as well. This uses
the exact same hardware path and clocks as generating the SPDIF signal. To do this,
we included an Audiophilleo1 feature under settings->SPDIF->Advanced->Test
Wave so that anyone can repeat these tests.
Using the 5120A we measured various carrier frequencies, calculated phase jitter
measurements from 10Hz to 100Khz and 1Hz to 100Khz and took the worst case
measurements to publish here. Although this test includes noise induced by the power
supply, output stage, and crystal clocks, it does not measure data correlated jitter. We
believe that this is not an issue because our design should have negligible data induced
jitter.
U S E R
M A N U A L
23
6
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