D*AP8
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The important step in calibration is to set up the
Operating Level
. A stationary sine signal at this level
must cause a FM carrier deviation of ±40kHz. If the input level (at FM HPA or uplink line) for this
reference modulation is known, just set the Operating Level in the
FM Conditioner
accordingly.
In most installations this will be the case.
In a lot of st6dBu (analog) or -9dBFS (digital) for a 500Hz tone is reference level. It may be
designated as the operating level and defined at 0dB relative (displayed on a peak level meter). Please
be careful with this type of reference level scale, as this analog operating level of 0dBr is not the same
as 0dBr MPX power!
If the reference modulation is unknown, a sine test tone needs to be applied and the frequency
deviation of the FM carrier needs to be measured over the air. Start with a generator level of -9dBFS
and change this value until ±40kHz deviation is attained. Please note that any Junger Audio unit in the
chain between generator and FM HPA needs to be bypassed first. Calibration is performed without any
processing, additional service or pilot signal considered!
If the Reference Level of your setup differs from -9dBFS the Setup Gain of the FM Conditioner can be
used for level matching.
