GUIDE TO INSTALLATION AND OPERATION
HCO-3901 |
23
Note: The ALC works with PCM audio. If non-PCM audio like Dolby-E or AC-3 is fed to the module, it will be ignored
and all the program channels will be bypassed to prevent interference with the other PCM audio channel
3.4.8.1 Config tab
Channels per program
Pull-downs are available to select the number of channels
per program. Depending on the ALC model, you may have
different possible selections, from 1 to 8 channels per
program.
Input channels selection
An input shuffler allows any combination of the available
channels to be used as inputs to each ALC program.
Note: An input channel cannot be assigned to more than
one (1) program.
Global Config - Mode
This pull-down selects the type of filtering that is applied to
the audio content of all programs:
•
EBU R128
•
A85 ITU-R BS.1770
•
ARIB TR-B32
Enable Loudness Monitoring
turns ON the ALC input and
output loudness monitoring for all programs.
3.4.8.2 PGM1-8 tabs
Loudness monitoring
When turned ON, the loudness meters display the program
input loudness (before ALC processing), the dynamic
correction applied by the ALC, the ALC limiter correction,
and the program output loudness (after ALC processing).
The input and output loudness are given in
dBFS
or
LKFS
,
depending on the selected ALC filter (dB without filtering,
LKFS for ITU-R BS.1770 filtering). Loudness meters are
integrated over a 10 second period using a “sliding-window”,
which is equivalent to the
Short-term
mode in Dolby’s LM100
loudness meter.
Dynamic and limiter corrections are always given in dB.
Each correction meter is integrated over a period of 250
milliseconds.
ALC Presets
Three factory presets for the ALC are available to cover
most broadcast applications.
•
Factory Light –
The ALC applies low dynamic range
compression on the audio program content. The overall
response time is relatively slow, which reduces the ALC
Figure 3.24 ALC – Config tab
Figure 3.25 ALC – PGM1 to PGM8 tab
