D&B D80, Manual

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Digital/Digital
NOTICE!
When both input pairs are set to «Digital» and locking to the sync
source is not possible, none of the inputs will receive any audio
signal.
If two digital signals are used at the same time, these signals must
be completely synchronous (i.e. must have the same synchronized
sampling rate).
Both input connector pairs 1/2 and 3/4 are set to «Digital», a 2-
channel digital audio signal is accepted by inputs 2 and 4
respectively.
The input connectors 1 and 3 are not available.
Locking to either 48 or 96 kHz is indicated below ( ). In
this case, the sync source is input 2.
When both input pairs are set to «Digital», either of them can be
selected as sync source.
Mixed
Input connector pair 1/2 is set to «Analog», an analog 2-channel
audio signal is accepted by inputs 1 and 2.
Input connector pair 3/4 is set to «Digital», a digital 2-channel
audio signal is accepted by input 4.
A3 by input 3 is not available.
Locking to either 48 or 96 kHz is indicated below ( ). In
this case, the sync source is input 4.
Clocking
To keep latency as short as possible, the system does not utilize
non-clocked (asynchronous) Sample Rate Converters (SRC).
The clock of the digital audio system is derived from an internal
crystal oscillator with a sampling rate of 96 kHz. Alternatively, the
clock can be derived from a signal fed to the digital inputs. The
sampling rate of this signal must also be 96 kHz. The derived clock
is PLL filtered to avoid possible jitter.
It is also possible to use a signal with a sampling rate of 48 kHz as
it is in even proportion to the required 96 kHz. In this case, the
system detects the sampling rate and automatically doubles it using
a synchronous sampling rate doubler to achieve the required
96 kHz. The required filtering is calculated using linear phase FIR
filters.
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