Orban OPTIMOD 8685, Operating Manual

Page: 64 / 357

2-10
INSTALLATION ORBAN MODEL 8685
E) Set today’s date.
F) If you want the clock to reset itself automatically to conform to Daylight Sav-
ing Time (Summer Time), use the
D
AYLIGHT
S
AVING
>
M
ONTH
/W
EEK
and
S
TANDARD
T
IME
M
ONTH
/W
EEK
. to match the daylight saving and standard times
in your area. If you do not wish to use this feature, leave the
D
AYLIGHT
S
AVINGS
and
S
TANDARD
T
IME
fields set to
O
FF
.
Note that the clock will set itself automatically if you have set the 8685 to
synchronize to an Internet timeserver. See
Synchronizing Optimod to a
Network Timeserver in page 2-59.
4. Decide whether you will keep the current Input/Output routing configu-
ration.
L
OCATE
to the Time & Date screen ( S
YSTEM
S
ETUP
> Q
UICK
S
ETUP
3 ).
To accommodate users who are re-running Quick Setup after they have made
customized routing assignments, it is possible to keep the current Input/Output
routing configuration or to use the factory default configuration.
5. Set the surround and 2.0 maximum low pass filter frequency as appro-
priate to your application.
The audio bandwidth of the 8685’s surround and 2.0 processors (10.0 to 20.0 kHz
in 1.0 kHz steps) can be set in three places: (1) in the active Setup, (2) in the EQ
page of the Modify screen, and (3) by remote control. The 8685’s bandwidth is
always the
lowest of these three settings. The frequency in Setup is a technical
parameter that determines the highest bandwidth available. The installing engi-
neer should set it to complement the sample rate of the digital system being
driven by the 8685. For example, if the 8685 is driving a system with a 32kHz
sample rate, set the
2.0 M
AX
L
OW
P
ASS
F
ILTER
to
15.0
KHZ
. That way, a setting of
20 kHz elsewhere will not cause excessive bandwidth and aliasing because the
8685 will automatically override it with the
MAX LPF
setting.
For ATSC digital television transmission (which uses 48 kHz sample rate), set the
2.0 M
AX
L
OW
P
ASS
F
ILTER
to
20 KH
Z
.
The
2
.0 M
AX
L
OW
P
ASS
F
ILTER
for the surround and 2.0 channel processing
are independent.
A)
L
OCATE
to the Lowpass Filter screen (
S
YSTEM
S
ETUP
> Q
UICK
S
ETUP
4
).
B) Set the
2.0 M
AX
L
OW
P
ASS
F
ILTER
control as required.
6. Set surround and 2.0 external AGC mode.
Most of the processing structures in the 8685 control level with a preliminary
AGC (Automatic Gain Control). In typical 8685 installations, there is no AGC up-
stream from the 8685. However, if you are using a suitable Automatic Gain Con-
trol ahead of the 8685 (to protect an STL, for instance), the AGC in the 8685
should be defeated. This is so that the two AGCs do not “fight” each other and
so they do not simultaneously increase gain, resulting in increased noise.
A)
L
OCATE
to Studio Configuration screen (
S
YSTEM
S
ETUP
> Q
UICK
S
ETUP
5
).