Orban OPTIMOD-FM 8600, Operating Manual

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OPTIMOD-FM DIGITAL INSTALLATION
2-35
You can lock the sample rate of each of the 8600’s AES3 outputs to the
sample rate of a reference AES3 signal that is applied to the AES3 input
or to an AES11 signal that is applied to the SYNC input.
If you wish to operate the two AES3 outputs at different sample rates,
only one output can be synced to the signal at the SYNC input. However,
in this case the other output could be synced to the signal appearing at
the digital input.
The selections for each of the two AES outputs are
I
NTERNAL
, S
YNC
I
N
,
and
I
NPUT
.
I
NPUT
sets a given AES3 output sample rate and synchronization to
the same sample rate present at the 8600’s AES3 (audio) input. Likewise,
S
YNC
I
N
uses the AES11 sync input’s sample rate and synchronization as
the source.
I
NTERNAL
synchronizes the given AES3 output rate to the
8600’s internal clock and uses the
S
AMP
R
ATE
setting to determine its out-
put sample rate.
For a given AES3 output, the output sample-rate selector (“
S
AMP
R
ATE
”)
has no effect in the
I
NPUT
and
S
YNC
I
N
modes unless sync is lost. Then the
output reverts to internal sync at the sample rate that is preset by the
sample-rate selector for that output. Otherwise, the output sample rate
follows the sample rate present at the selected input regardless of the
setting of the output sample rate selector.
If no signal is provided to the 8600 digital input or
S
YNC
I
N
, set
SR S
YNC
to
I
NTERNAL
and select the desired output sample rate.
MPX hardware provides a sync reference input (labeled
R
EF
I
N
) on a fe-
male BNC jack at the end of the breakout cable that connects to the digi-
tal composite connector. It accepts a 1x 5V p-p squarewave wordclock
signal at 32, 44.1, 48, 88.2, or 96 kHz, or a 10 MHz sinewave or
squarewave signal, 0.5 to 5 V peak. 10 MHz is a common output frequen-
cy produced by GPS and rubidium frequency standards. You can config-
ure the 8600 to lock its 19 kHz pilot tone and output sample frequency to
this input.
When a valid reference signal is applied to this input, it locks the Opti-
mod’s Internal DSP clock to this input, so if a given AES3 L/R output’s sync
source is set to Internal, the sample frequency at that output will be
locked to this reference signal. This will also lock the 192 kHz sample rate
of the digital composite output and the pilot tone frequency appearing
at both the analog and digital composite outputs to the reference signal.
See Digital Composite Outputs on p. 2-11, Digitized Subcarrier Inputs on
p. 2-11, and Wordclock/10 MHz Sync Reference Input on p. 2-11
H) Set the desired output
W
RD
L
ENGTH
(word length).
[14], [16], [18], [20], or [24] bits
The largest valid word length in the 8600 is 24 bits. The 8600 can also
truncate its output word length to 20, 18, 16 or 14 bits. The 8600 can also
add dither and you should set it to do so if the input material is insuffi-
ciently dithered for these lower word lengths. (See the next step.)
I) Adjust
D
ITHER
to
I
N
or
O
UT
, as desired.