HE4000 Encoding System
Overview
There are four audio channels (stereo pairs) each independently configurable for:
•
MPEG-1, Layer 2
•
Dolby® 2-channel encoding (AC3 2.0)
•
Dolby® E/uncompressed supported via SMPTE 302M
•
Pass-through (e.g. for externally encoded AC-3 5.1)
Audio input is AES/EBU digital and the encoding is balanced analog.
The HE4000 supports compressed audio output rates of 64 to 384 Kbps and four different audio
channel compression methods.
1.0.3 Auxiliary Data
One channel of synchronous data 1 bps up to 20 Mbps (RS-422) and one channel of
asynchronous data 1200 – 38400 bps (RS-232) are supported by the HE4000.
1.0.4 Conditional Access
The HE4000 (optionally or standard) supports BISS, Modes 1 and E, as well as
ComtechTV’s proprietary conditional access schemes.
1.0.5 Modulator
The HE4000 has an optional built-in DVB
®
-compatible QPSK, 8PSK and 16QAM modulator with
a 70 MHz, 140 MHz, and direct L-Band output carrier capable of supporting up to 45 Msps. An L-
Band monitor output, 50 Ohm F type connector, is provided for direct IRD connection
.
1.0.6 Modulator Control Buttons
The HE4000 provides dedicated modulator control buttons on the front panel. These are
designed to bring carriers up onto satellites in a fast and efficient manner.
1.0.7 ASI Output
An ASI output is also available for connection to an external multiplexer or modulator.
The HE4000 accepts all commonly used video and audio input formats and provides an MPEG-2
DVB compliant transport stream in addition to a DVB
®
-compatible QPSK modulator with a 70
MHz, 140 MHz, and direct L-Band output.
Within the data rate limitations of the channel, the HE4000 can be reconfigured for different video
resolutions, video optimization, and audio compressed bit rates to get the best video
performance. Higher compressed bit rates result in better-decoded video quality.
In addition, the HE4000 can automatically configure the video and audio rates in order to match
the available transmission bandwidth for optimum performance.
1.0.8 Monitor and Control Functions
The HE4000 monitor and control functions include:
•
Fault Relay with passive normally open and normally closed contacts .
•
Front panel operator control utilizing an easy-to-use, intuitive menu and backlit push
buttons.
01-0951-404 Rev B
1-3
