Cobalt Digital Inc 3G Fusion 9931-EMDE Product Manual page 19

Introduction
Figure 1-6 Downmixing Functional Block Diagram with Example Sources
9931-EMDE-OM (V1.17)
Embedded, AES, and analog input channel pairs also have displays showing
slow-ballistics true peak levels for each pair. Embedded and AES channels at
digital silence signal level show Mute; analog channels with levels below -96
dBFS digital equivalent show Silence.
Output audio rates are always 48 kHz locked to output video, but discrete
AES inputs can pass through the sample rate converters to align these inputs
with the output timing. Output AES is always precisely synchronized with the
output video. The balanced analog audio input is sampled at 48 kHz with a
+24 dBu clipping level (+24 dBu => 0 dBFS).
Note: AES Dolby-encoded inputs routed directly to card optional Dolby decoder are
detected and use a special path that automatically bypasses SRC.
Audio Input Routing/Mixing Function
(See Figure 1-5.) The input routing function provides gain and mute controls
for each input signal. Following these controls, selected inputs can directly
exit the input routing function and be applied to the internal bus, or first be
applied to one of four downmixers or flex mixers.
Downmixers. (See Figure 1-6.) Four independent downmixers (
thru
Downmix-D
®
discrete, Dolby
( ), Center ( ), Left Surround (
R C
signals to be multiplexed into a stereo pair. The resulting stereo pairs
Downmix-A(L/R)
like any of the other audio sources described earlier.
Embed Ch 1 - Ch 16
AES Ch 1 - Ch 16
AN-AUD Ch 1- Ch 8
Embedded Ch 1
Embedded Ch 2
AES Ch 6
Embedded Ch 4
Embedded Ch 5
Automatic Downmixer.
) allows monitoring a selected stereo pair for a user-configurable signal
+ADM
level threshold. If this threshold is not achieved within a configurable holdoff
time, the automatic downmixing develops a stereo downmix from selected
alternate multi-channel sources (developing an automatic downmix as
described for Downmixers above).
9931-EMDE PRODUCT MANUAL
9931-EMDE Functional Description
) provides for the selection of any five embedded, AES
decoded, or analog audio sources serving as Left (
), and Right Surround (
Ls
thru can in turn be routed and processed just
Downmix-D(L/R)
Ls
L
Downmix-A(L)
A
C
R Downmix-A(R)
Rs
Downmix-A
L
) individual
Rs
To Internal Bus
Automatic downmixing (option
), Right
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