Cobalt Digital Inc 9922-FS, Руководство по эксплуатации продукта, Страница: 20 / 118

1
9922-FS Functional Description
1-16
9922-FS PRODUCT MANUAL 9922FS-OM (V1.5)
Audio Events Detect Function
Option
+QC
provides a
Audio Detect Events
user interface and an
Event
Triggers
user interface for checking user-selected channels to detect audio
silence conditions. The
Event Triggers
user interface in turn allows instructing
the card as to the action to take upon an event (such as go to a changed signal
routing, activate a GPO, send an automated email, or go to a user-defined
preset).
2.0-to-5.1 Upmixer
Option
+UM
provides a 2.0-to-5.1 upmixer function that receives a normal
PCM stereo pair from any internal audio bus channel pair. The stereo pair is
upmixed to provide 5.1 channels (Left (
L
), Right (
R
), Center (
C
), Low
Frequency Effects (
LFE
), Left Surround (
Ls
), and Right Surround (
Rs
)).
Whenever the upmixer is active, it overwrites the six selected 5.1 output
channels with the new 5.1 upmix signals (including replacing the original
source stereo
L
and
R
inputs with new
L
and
R
signals).
The 2.0-to-5.1 upmixer can be set to upmix in any of three modes: Always
upmix, Bypass upmix, or Auto enable/bypass upmixing. The Auto upmixing
mode looks at the signal levels on the selected channels and compares them to
a selectable level threshold. It then determines whether or not to generate 5.1
upmixing from the stereo pair as follows:
•
If the upmixer detects signal level below a selected threshold on all
three of the selected channels designated as
C
,
Ls
, and
Rs
, this
indicates to the upmixer that these channels are not carrying 5.1. In
this case, the upmixer produces new 5.1 content generated by the
upmixer.
•
If the upmixer detects signal level above a selected threshold on any
of the three selected channels designated as
C
,
Ls
, and
Rs
, this
indicates to the upmixer that the channel(s) are already carrying
viable 5.1 content. In this case, the upmixer is bypassed and the
channels fed to the upmixer pass unaffected to the upmixer outputs.
The examples in Figure 1-6 show the automatic enable/disable upmixing
function applied to example selected channels
Bus Ch 1
thru
Bus Ch 6
. As
shown and described, the processing is contingent upon the signal levels of
the channels selected to carry the new 5.1 upmix relative to the selected
threshold (in this example, -60 dBFS).