8218 Digital - Orban 8218 Operating Manual

8218
Digital
Stereo
Encoder
INTRODUCTION
8218
Digital
FM
Stereo
Encoder
More
and more
FM
stations
are transporting
their
audio
digitally,
from
studio
to transmitter.
However,
digital
links typically
handle left/right
rather
than composite.
Orban's
8218
Digital
FM
Stereo
Encoder can
extend your
all-digital
performance through
to
the stereo
encoder.
It's
designed to
perfectly
complement
Orban's
OPTIMOD-FM
digital
audio
processors
in
an
all-digital
transmission system.
All
encoding
is
done
entirely in
the
digital
domain
by a
dedicated
DSP
chip,
producing
two
analog composite
outputs
with outstanding
specifications
and long-term stability.
The
8218
accepts
either
analog or
AES/EBU
digital inputs.
The
digital
input automatically
synchro-
nizes to
and
de-jitters
any standard
incoming sampling
rate.
In addition,
it
responds
to status
bits in
the
AES/EBU
data
stream that
may
be used
to
turn
de-emphasis
on
or
off.
This feature
allows automatic switching of pre-emphasis and/or J.17
(NICAM)
de-emphasis to
accom-
modate
different
transmission
schemes.
An
Overshoot
Control Limiter
can be applied
to
the
incoming audio, limiting
overshoots to
less
than
0.5dB while introducing
minimal
(or
no) audible artifacts
and
without contaminat-
ing the
baseband spectrum above 57kHz.
The Overshoot
Control Limiter
is
particularly
useful
if
the
processed audio has
been passed to the
8218 through a
digital
STL
that
uses
lossy
encoding,
like
MPEG,
Dolby, or
APT-X. The Overshoot
Control Limiter uses
lookahead
techniques, and,
when
activated,
adds
a time delay
of
4 milliseconds
to
the stereo
encoding process.
Features
• >70dB
separation,
20Hz- 15kHz.
• <-90dB
noise
and
distortion (after
de-emphasis,
and referenced to
100% modu-
lation output).
•
Digitally-created
composite signal,
from
either
analog
or
AES/EBU
digital input.
The 8218 also accepts
two
analog
SCA
inputs,
and
sums them
with analog
composite output.
The
analog composite appears
on
two
outputs,
each with
individual level control.
•
Built-in
sample
rate
converter that
allows
8218
to
accept
any
digital
AES/EBU
input
sample
rate
between
32kHz and 48kHz.
•
Recessed
front
panel controls for selecting
Input type (Analog/Digital), Ste-
reo/MonoL/MonoR mode,
Pilot
On/Off, and Crosstalk
Tests.
• Front panel metering of Left
and Right inputs plus
Composite
or Pilot
outputs.
•
Recessed
front
panel multi-tum screwdriver potentiometers for
Analog
Left,
Analog
Right,
and Digital input levels,
as well as for
Pilot,
Composite
#1,
and
Composite #2
output
levels.
•
Recessed
rear
panel
DIP
switch for selecting
pre-emphasis In/Out,
pre-emphasis
type (50ps/75(J.s),
J.17
de-emphasis In/Out,
and whether or not
the stereo
en-
coder's
pre-emphasis
and
J.17
de-emphasis
settings
respond to status bits
of the