User manual

SETUP OF DISCRETE (L & R) AUDIO OUTPUT ENG
Page 46
23.6 DIGITAL AUDIO OUTPUT PRE-EMPHASIS (ST VERSION ONLY)
The digital audio output (available as an option on the ST model) follows the same settings of discrete analog audio (ref
to previous Section).
Jumper
s CN 17 and CN 18 must not be set!
23.7 CHANGING THE OPERATING MODE (OUTPUT MODE)
The Output Mode function allows you to select from among three different equipment operating modes:
- Normal operation
- Peak Reference Tone
- Processor ByPass
The Normal operation allows normal use of the equipment and all of its functions.
In Peak Reference Tone mode, a reference tone of 400 Hz is output on the Analog Out output, as well as on the MPX
Out ** output consisting of a 400 Hz/ 0 dB tone + 19 kHz / - 20 dB pilot tone *****.
The Peak Tone identifies the maximum peak value of the audio and MPX signals reached by the processor while it is
operating. This peak corresponds to the maximum frequency deviation. This allows you to set the levels for the entire
sound chain simply and safely.
In Processor ByPass mode, all the processing sections are disabled (AGC system, audio processing and pre-emphasis
circuit). It allows you to carry out tests and reference measurements.
The Warning LED is lit when Peak Tone Reference and Processor ByPass mode are activated.
Once you have identified this function within the Output Calibration submenu, use the shuttle to select:
- Normal operation
- Peak Reference Tone
- Processor ByPass
** This is an optional plug-in
***** The pilot signal may be disabled by selecting the Off option within the MPX module menu before enabling the Peak
Reference Tone mode.
23.8 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.
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!