Crystal Vision
Statesman
The second mode uses built-in phase locked loops and VCOs to accept an AES reference
which may vary from below 30 kHz to above 50 kHz. This is referred to as ‘Auto’ mode,
and should be used when the AES reference sample rate is outside 48 kHz +/- 50 PPM.
Notes:
‘Auto’ mode can only be used with an AES reference. The ‘Xtal’ mode is designed for use
with a video, word clock or AES reference at 48kHz.
GPI connections to the Auto/ Xtal mode change line will override the card edge switch if
asserted to a logic low or grounded.
Selecting the reference
The ADCA412 output clock may be locked to AES reference, word clock, analogue video
(or black and burst) or left to run off a 48kHz internal clock. References that are available
will be shown with a green indicator.
Make the required reference selection with the mouse by placing a selection dot against
an available clock source.
Note:
If a reference source is selected that is not there or is lost, the module will automatically
attempt to select one that is present. If no external reference can be found the internal clock
will be selected.
Channel swapping, single channel mode and phase inversion
Channel routing logic following the silence detection circuits allows the incoming
analogue signals to be assigned to digital outputs in a variety of ways.
The possible variations are as follows:
•
channels may be swapped so that Input 1 feeds AES Output 2 and Input 2 feeds AES
Output 1
•
both output stages may be assigned to either Input 1 or Input 2 effectively doubling
the duplicate outputs for a single analogue input.
•
the phase of the right output of AES Output 1
OR
AES Output 2 may be inverted
Make the selection with the mouse by placing a selection dot against the required options.
Note:
GPI connections to the shuffling mode lines will override card edge switches if asserted to a
logic low or grounded.
Selecting silence options
Each input channel is equipped with ‘near silence’ detectors. If the audio signal levels are
sustained at below –50dBFS for more than a selected period of time, an indicator for each
channel comes on and an appropriate GPI output can be asserted low.
To change the time required for a sustained silence to raise alarms and display warnings
click on the Silence Time drop down box and select from the following range:
1.5 seconds
8 seconds
every 8 seconds until… 120 seconds
ADCA412 User Manual R2.1
7
30 October 2018
