Chapter 6 Audio Modules
AHC-RAC Module
© 2015 Harmonic Inc. All rights reserved.
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Electra 9200, Rev O
n
On the encoders, the digital audio ports are DGTL AUD1, DGTL AUD2, DGTL AUD3. The
port labeled DGTL AUD4 is unused.
n
For multi-channel audio, use three cables to connect the surround mix, connecting L/R to
DGTL AUD1, C/Lfe to DGTL AUD2, and Ls/Rs to DGTL AUD3, which maps the channels
to AES3 pairs as defined by SMPTE 320M. The fourth connector is not used.
AHC-RAC Audio Encoding Features
Table 6–4: AHC-RAC Audio Encoding Features
Feature
Support
Digital input
n
Digital multi-channel or multiple stereo inputs
n
One 5.1 surround, or three stereo pairs per card (surround mix
on three AES3 signals with channels mapped per SMPTE
320M (L/R, C/Lfe, Ls/Rs)
Input format
n
Digital: AES/EBU, S/PDIF, IEC60958
n
Embedded: from SDI (synchronous to video)
Audio encoding
format
n
MPEG-1 Layer II 2.0 (stereo) compression
n
AC-3 single 5.1 or multiple 2.0 compression
a
n
AC-3 metadata input
n
AC-3 (2.0 or 5.1) pass-through
n
AAC/HE AAC single 5.1 or multiple 2.0 audio compression
with either MPEG-2 or MPEG-4 encapsulation
a
n
Single channel, dual, stereo, and joint stereo (MPEG-1 Layer II
and AAC/HE AAC only)
n
Single PID per Channel support with MPEG-1 Layer II
Extraction from serial
digital video (48 kHz
sampling only)
n
MPEG-1 Layer II
n
Select up to three pairs
a.
requires optional firmware license.
AHC Coding Mode, Sampling Frequencies, and AES Bit Rates
The AHC-RAC modules accept discrete AES3/SPDIF digital, or AES3 embedded in HD/SD
serial digital video inputs. For discrete AES3 inputs, sampling frequencies of 48 kHz, 44.1
kHz, and 32 kHz are supported. Embedded in digital video is supported only for 48 kHz
sampling, which must be synchronous to the video.
