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IN / OUT SETTINGS (ST version) ENG
Page 45
14.3 HOW TO CONFIGURE THE AUDIO OUTPUT (AUDIO MODULE SETUP)
14.3.1 SETTING THE PREEMPHASIS
The Audio Module Setup / Preemphasis menu allows You to select one of the following options:
- 50uSec Internal
pre-emphasis enabled
on the processor audio outputs at 50 usec
- 75uSec Internal
pre-emphasis enabled
on the processor audio outputs at 75 usec
- 50uSec External
pre-emphasis disabled on audio outputs (an external 50 usec preemph. must be applied)
- 75uSec External
pre-emphasis disabled on audio outputs (an external 75 usec preemph. must be applied)
European countries use a 50 uSec preemphasis, while US countries use a 75 uSec preemphasis.
The processor generates two types of pre-emphasis: dynamic and fixed. The former may vary in relation to the
modulation peak, thereby considerably increasing the average modulation within the maximum deviation of
75KHz, while the latter is fixed at 50 or 75uSec depending on the country in which it is used. The latter may be
removed from the analog audio outputs if necessary, while the first is always present to ensure proper modulation
at all times.
ONLY ONE
PRE-EMPHASIS MUST BE KEPT ACTIVE IN A TRANSMITTING CHAIN.
IT IS HIGHLY RECOMMENDED TO USE THE PRE-EMPHASIS WITHIN THE PROCESSOR AND
TURN OFF THE ONE GENERATED BY EXTERNAL TX OR MPX CODERS.
NOTE: MAKE SURE YOU HAVE PREEMPHASIS SET TO THE APPROPRIATE VALUE FOR YOUR
APPLICATION BEFORE CALIBRATION AS THIS WILL AFFECT THE OUTPUT LEVEL