A D 2 4 0 2 - 9 6 - O P E R A T I N G M A N U A L
data loss, and will reduce the maximum transmission distances.
Standard analog
audio cable should
not
be used for digital signals.
The Digital “In” connector
accepts either
professional or consumer
status bit formats. The PLL
automatically supports 1:1, and 2:1 lock ratios when a fixed sample rate is selected. In other
words, a 48-kHz digital audio signal may be used as a reference when the converter is operating at
96 kHz. However, the varispeed mode (“VAR”) requires a 1:1 lock ratio.
A digital audio input is required when:
•
The converter will be operating in a variable speed mode (“VAR 1:1”).
•
More than two channels must be phase locked together.
•
The converter is to be locked to an external studio reference.
•
The digital-to-digital (“D-to-D”) mode is selected.
If a reference is required, but no reference input is detected, the “LOCK” LED will flash
rapidly. If a reference is present, but lock has not been achieved, the “LOCK” LED will flash
slowly.
Note: Using an external reference will not degrade or alter the low-jitter performance
of the AD2402-96 converter at any of the fixed sample rates.
The jitter
performance of the fixed sample rate modes is maintained even when the
reference has relatively high levels of jitter.
However, the “VAR”
variable speed mode has a wide frequency range
that
precludes the use of the final VCXO stage of the AD2402-96 PLL.
If a variable
speed mode is used, it is important to provide a low-jitter reference signal.
Use
the fixed sample rate settings whenever possible.
Digital-to-Digital processing functions include;
Word Length Reduction, Pro to Consumer and
Consumer to Pro channel-status conversion, SPDIF to AES/EBU and AES/EBU to SPDIF
conversion, SCMS override, and 75 ohm unbalanced to 110 ohm balanced conversion. The D-to-
D feature also allows the AD2402-96 to act as a 1 in 4 out digital distribution amplifier.
In most 2-channel recording applications it is not necessary to connect a signal
to the “Digital Input” connectors.
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