Nautel NV15, Operation And Maintenance Manual

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NV15/NV20 Operations and Maintenance Manual Operating the transmitter
Page 2-58 Issue 3.2 2013-10-01
– AGC Limiter:
select
Enabled
, then enter
AGC Limit
percentage (allowable
range is 0-160%, defaulted to 120%) and
Time Constant
(allowable range
is 0-1000 ms, defaulted to 0 ms). If
Enabled
, when the modulation level
exceeds the AGC Limit, the gain of the audio input will instantly decrease
in order to reduce the modulation level below the AGC limit threshold.
Recovery from this audio gain reduction is dependent on the
Time
Constant
delay (fast attack, slow recovery). The input signal is briefly
distorted by the audio gain reduction when the threshold is exceeded.
– Two Slope Limiter:
if
Enabled
, when the modulation level exceeds the
Threshold
, the gain of the audio input will instantly change according to
the gain percentage setting (percentage of the initial gain, that which is
below the threshold). The input signal is distorted by the audio gain
change.
–Threshold
(allowable range is 0-160%, defaulted to 120%).
–Gain
(allowable range is 0-100%, defaulted to 56.2%).
– L/R Limiter:
this look-ahead limiter can be applied to the signal
immediately before the stereo generator in the exciter. It has a fixed attack
time (and corresponding delay) of approximately 1 ms. It can be
configured to reduce the signal, if the gain setting is 0 dB or less, or can be
used to perform an AGC function and boost quiet sections of the audio if
a positive gain setting is used. If
Enabled
, enter the following parameters:
–
Max Gain
(allowable range is -20 to 20 dB, defaulted to 0 dB).
–
Decay Time
(allowable range is 0 to 60 s, defaulted to 0 s).
–
Hold Time
(allowable range is 0 to 60 s, defaulted to 0 s).
–
MPX Power Limiter:
if
Enabled
, enter MPX RMS Limit . This limit
allows the broadcast signal to remain in compliance with the MPX power
limits as suggested in ITU-R BS.412-9. While the limiter will keep the
transmitter in compliance, it is recommended that adjustment to the
processing be made in such a way as to minimize the reductions
performed by the limiter. Otherwise, the signal will not take advantage of
the peak modulation capability available.
–
MPX RMS Limit
(allowable range is -12 to 12 dBr, defaulted to 0 s).