Orban OPTIMOD-FM 5700i, Operating Manual

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OPTIMOD-FM DIGITAL INSTALLATION
2-31
processed output when the 5700i’s output is set F
LAT
. This can introduce
overshoots in the overall transmission chain.) However, if you cannot de-
feat the pre-emphasis in your stereo encoder or if you will use the analog
output for monitoring, set the output
F
LAT
.
If you are sending the analog output of the 5700i 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.
If you are going to use the analog output for headphone monitoring [see
step (B) below], set the output
F
LAT
.
B) Set the
AO S
OURCE
to
FM
,
FM+D
ELAY
,
or
M
ONITOR
.
FM: This produces a fully peak-controlled output suitable for driving a
transmitter.
FM+Delay: This produces a fully peak-controlled output suitable for driv-
ing a transmitter. Up to 16 seconds of diversity delay can be applied to
this output. To set the amount of delay, refer to step (9.F) on page 2-30.
Monitor: If you do not need the 5700i’s analog output to drive a trans-
mitter, you may configure it to receive the output of the multiband com-
pressor before peak limiting. This signal is suited for driving headphones.
The input/output delay is approximately 3-8 milliseconds (depending on
the setting of
AGC C
ROSSOVER
T
YPE
)
. Even though normal 5700i presets
have a delay of about 15 ms, which most DJs, announcers, and presenters
can learn to use without discomfort (although they may need some time
to become accustomed to it), the low-delay output will cause less bone-
conduction comb filtering. However, in most cases, the low-delay output
will not be necessary to ensure adequate talent comfort.
The normal delay is 15 ms except for “UL” (ultra-low latency) presets,
which have approximately 5 ms delay.
If have set the source to Monitor, be sure to set analog pre-emphasis to
Flat. See step (A).
C) You can use either program material or tone to set your output level (and
thus, your on-air modulation). If you want to use tone, turn on the 100 Hz cal-
ibration tone and set it to 91%.
The tone is calibrated with reference to the composite output and as-
sumes 9% pilot injection: 91% + 9% = 100%. The peak level at the ana-
log output is now the same as the maximum peak level under program
conditions when the
AO P
RE
-
E
control is set to
P
RE
-
E
.
This peak level should agree with the setting of the
AO 100%
control.
AO
100%
is equal to the RMS value of a sinewave whose peak value is equal
to the maximum peak output of the analog output under program con-
ditions if the
AO P
RE
-
E
control is set to P
RE
-
E
.
For example, when AO P
RE
-
E
= +10.0 dBu, the peak output is 5.77 volts, which corresponds to a sin-
ewave whose RMS values is 4.08 volts. Program material peaks of fre-
quent recurrence will not exceed 5.77 volts peak.
See step (9.H) on page 2-30 for instructions on how to turn on the cali-
bration tone and set its frequency and level.
D) Using the
AO 100%
button, set the desired analog output level corresponding
to 100% modulation, using units of dBu (0 dBu = 0.775 Vrms).