Orban OPTIMOD-FM 8600Si, Operating Manual

Page: 89 / 356

OPTIMOD-FM DIGITAL INSTALLATION
2-33
B) Set the
DO P
RE
-E
control to
P
RE
-E
(for pre-emphasis),
P
RE
+J17
,
J.17
or
F
LAT .
C) Set the
DO R
ATE to 32, 44.1, 48, 88.2, or 96 kHz.
The 8600Si’s fundamental sample rate is always 32 kHz, ensuring that the
output bandwidth is always strictly limited to 16 kHz and that the proc-
essed signal can be passed through a 32 kHz uncompressed STL without
addition of overshoot. However, the internal sample rate converter sets
the rate at the 8600Si’s digital output. This adjustment allows you to set
the output sample rate to ensure compatibility with equipment requiring
a fixed sample rate.
D) Set the
P
ILOT
S
YNC
.
The
P
ILOT
S
YNC
control determines the reference frequency source to
which the 19 kHz pilot tone frequency is locked. (To do this, the DSP clock
is locked to this frequency.) The choices are
D
IG
I
N
(the AES3 signal ap-
pearing at the 8600Si’s XLR digital input),
R
EF
I
N
(the 10 MHz or 1x word-
clock applied to the 8600Si’s
R
EF
I
N
BNC connector), or
I
NTERNAL
(the in-
ternal crystal-controlled DSP clock oscillator).
•
If D
IG
I
N
is chosen and no valid signal is available at the unit’s digital input, the
8600Si automatically switches the sync source to the R
EF
I
N
BNC connector. If
there is no valid digital input signal at the reference input, the sync source de-
faults to the 8600Si’s internal clock.
•
If R
EF
I
N
is chosen and there is no valid input signal at the R
EF
I
N
BNC connec-
tor, the sync source defaults to the 8600Si’s internal clock.
E) Press Next . Then set the
DO S
YNC .
You can choose
P
ILOT
S
YNC (the DSP clock frequency reference as deter-
mined by the
P
ILOT
S
YNC control) or
D
IGITAL
I
N (the output sample rate is
synchronized to the sample rate appearing at the 8600Si’s XLR AES3 in-
put).
•
If
D
IGITAL
I
N
is chosen and no valid signal is available at the unit’s digital input,
the 8600Si automatically switches the sync source to the source determined by
the
P
ILOT
S
YNC
control.
F) Set the desired output
W
ORD
L
ENGTH
.
[14], [16], [18], [20], or [24], in bits
The largest valid word length in the 8600Si is 24 bits
The 8600Si can also truncate its output word length to 20, 18, 16 or 14
bits. The 8600Si can add dither for input material that is insufficiently
dithered for these lower word lengths (see the next step).
G) Adjust
D
ITHER
to
I
N
or
O
UT
, as desired.
[In] or [Out]
When set to In, the 8600Si adds “high-pass” dither before any truncation
of the output word. The amount of dither automatically tracks the set-
ting of the
W
ORD
L
ENGTH
control. This is first-order noise shaped dither
that considerably reduces added noise in the midrange by comparison to
white PDF dither. However, unlike extreme noise shaping, it adds a max-