Broadcast Electronics Marti GRX, Руководство пользователя и по обслуживанию, Страница: 32 / 45

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This field sets the main LF input channels sensitivity, i.e. multiplex, left and right channel. Note that
the multiplex and right channel share the same circuitry and the sensitivity is set to the same value
for all audio /multiplex channels, with a differential error (<0.2dB) at any level. Adjustment range is
- 3.5 - +12.5 dBm.
The upper line of the display shows the modulation corresponding to the LF signal currently present,
while the bottom line shows the nominal input level for 100% modulation, (75kHz). Increasing the
nominal input level consequently reduces the modulation, if the modulating signal remains constant.
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Field #25: Auxiliary Input Level setup
AUX 2.0kHz -31.5dB
Nom.input = + 0.0dBm
This field adjusts the auxiliary channels input sensitivity. Adjustment range is -12 - +4 dBm to
produce 10% modulation, corresponding to the deviation of 7.5kHz or -20dB in the upper line of the
display. On this line the actual modulation of the channel is shown in real time. On the lower one the
nominal value of the sensitivity in dBm, the parameter on which we act in this screen.
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Field #26: Limiter setup
MPX Limiter + 7.1dB
ON
This field sets the limiter action. Threshold level and enable / disable can be adjusted separately. The
limiter may be set to the maximum allowed modulation level for 75kHz-peak deviation, (0dB), so that
the transmitter prevents signals which would exceed this value, or if regulations allow, the limiting
value may be slightly higher to provide some dynamic headroom for some occasional modulation
peaks
It is recommended, not to frequently exceed the limiter threshold with modulation peaks.
Repeatedly exceeding the threshold can cause a heavy audible distortion.
Conversely, setting the threshold to high above the corresponding deviation level would be no
difference with the limiter on or off