Orban OPTIMOD-FM 8700, Operating Manual

Page: 83 / 390

OPTIMOD-FM DIGITAL INSTALLATION
2-21
[Skip this step if you are not using the digital input.]
a) Adjust the D
IGITAL
I
NPUT
R
EFERENCE
so that the meter reads an average of
10 dB gain reduction.
[

30 to –10 dBFS (VU), or –23 to –3 dBFS (PPM)] in 0.5 dB steps.]
The
D
IGITAL
R
EFERENCE
L
EVEL
VU
and
PPM
settings track each other with
an offset of 8 dB. This compensates for the typical indications with pro-
gram material of a VU meter versus the higher indications on a PPM.
If you know the reference VU or PPM level that will be presented to the
8700i, set the
D
IGITAL
R
EFERENCE
L
EVEL
to this level, but do verify it with the
steps shown directly below.
b) If the AGC gain reduction meter averages less than 10 dB gain reduction
(higher on the meter), re-adjust the D
IGITAL
R
EFERENCE
L
EVEL
to a lower
level.
c) If the AGC gain reduction meter averages more gain reduction (lower on
the meter), re-adjust the D
IGITAL
R
EFERENCE
L
EVEL
to a higher level.
This control has no effect on the analog inputs.
D) Select primary Input Source:
Using the S
ET
I
NPUT
T
O
field, set the input to the source (analog, digital,
or DIG+J17) that you will use for normal programming.
DIG+J17 applies J.17 de-emphasis to the incoming digital signal. It is only
applicable to certain STLs (like NICAM) that use this type of preemphasis
and that have not applied their own de-emphasis prior to their3 AES
outputs.
7. Configure output.
A) Locate to the Output Configuration screen ( S
YSTEM
S
ETUP
> Q
UICK
S
ETUP
6 ).
B) Set the A
NALOG
O
UTPUT
P
RE
/ F
LAT
control to P
RE
-E (for preemphasis) or F
LAT
.
[Skip this step if you will not be using the analog output.]
If you will use the analog output to drive a stereo encoder, P
RE
-E pro-
vides the best performance because this stereo encoder does not have to
restore the preemphasis. However, if you cannot defeat the preemphasis
in your stereo encoder, or if you will use the analog output for monitor-
ing, set the output
F
LAT
.
If you are sending the output of the 8700i through a digital link that uses
lossy compression (like MPEG, APT-X, or Dolby), set the output
F
LAT
. Lossy
codecs cannot handle pre-emphasized signals.
C) Set the D
IGITAL
O
UTPUT
#1 P
RE
/ F
LAT
control to P
RE
-E (for preemphasis), F
LAT
,
or P
RE
-
E
+J17 .
[Skip this step if you will not be using the “AES1” digital output.]
(See the notes immediately above.)