I/O CALIBRATION AND SYSTEM SETUP
ENG
Page 57
19.15 POWER LIMITER CONTROL ITU 412 (ST VERSION ONLY)
The ITU BS-412 regulation aims to reduce the density of the modulated signal while maintaining the same
peak deviation level in order to ensure minimal or limited co-channel interference.
The BS-412 definition says:
“It is assumed that the maximum peak deviation of +/- 75 kHz is not exceeded. Moreover, it is assumed that
the power of the complete multiplex signal (including pilot-tone and additional signals) integrated over any
interval of 60 seconds is not higher than the power of a multiplex signal containing a single sinusoidal tone
which causes a peak deviation of +/- 19 kHz.”
It is possible to adjust the output so that it will adhere to the BS-412 regulation.
WARNING!
The POWER LIMITER default setting is Off. Many European countries are enforcing
ITU-R 412 recommendation. However, if your country’s laws do not require the use of
the MPX Power Limiter, make sure that the Power Control is set to off, or severe loss
of loudness will result!
E.g, whit the ITU BS-412 Power Limiter set to on at 0.0dB, there are approximately 5
to 8 dB loudness loss over the limiter being switched off!
To enable the output power limiting:
DEFAULT SCREEN
OUTPUT CALIBRATION menu
POWER LIM(ITER) page
OUTPUT POWER LIMITER
The output power calculation does not take into account the injection values of the Pilot,
external RDS signal and possible SCA signals. The following values are therefore assumed
by default in the power calculation:
Pilot = - 20dB, Rds = - 31.5dB, Preemphasis = 50 uSec, No SCA signals
Whenever RDS or Pilot levels are different from the default ones, the processor has enough adjustment
available (Ref. Adj) on it that allows the processing to be compensated in order to keep the modulated signal
within the BS-412 limits.
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