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Bosch Security Systems | 2011-02
Praesideo 3.5 | Installation and User Instructions | 9 | System Configuration en | 406
8 Select the attenuation range from the AVC range
dropdown list.
9 Go to the Audio processing page of the audio input to
which the sensing microphone is connected. A
screen similar to the one in figure 49.2 appears.
10 Click the Start AVC calibration button to start the
calibration of the AVC. This results in a loud wobble
tone (duration: 15 s) in the zones that use this audio
input to measure the ambient noise level. After the
wobble tone, there will be a silence (duration: 15 s).
Then a notification appears with the calibration
result. The zone is not available for calls during
calibration, because all audio outputs in the zone are
used to distribute the calibration tone.
Temporarily reset extremely long audio delay
settings (> 2 s) of the power amplifiers to a low value
to avoid that the wobble tone is not yet present when
calibration of the AVC starts.
The following messages can appear during or after
calibration:
• AVC calibration running
Displayed during the calibration process.
• AVC calibration completed, range = x dB
Displayed after successful calibration. The range
shows the available AVC range in this situation. The
sum of the AVC range and the call margin that is
configured for a zone should be less than the
indicated available range.
• AVC calibration failed: sensing signal too high
Input overloaded by a ambient sensing signal that is
too high. Use a less sensitive microphone, use an
attenuation pad, or choose a different sensing
location.
• AVC calibration failed: available range too small
The difference between the measured ambient
sensing signal with and without calibration tone is
less than 6 dB. The available Praesideo output level
is too low compared to the existing ambient noise at
the sensing location.
• AVC calibration failed: ambient sensing input or its unit is
defect or disabled
AVC calibration and AVC is not possible with a
defect or disabled audio input for the ambient
sensing signal.
• AVC calibration failed: no AVC output is available
AVC calibration and AVC is not possible without a
zone being configured for AVC using this audio
input for sensing. The calibration tone cannot be
broadcast.
Note
A value of 12 dB is a practical value. A higher
value will result in lower call volume levels when
the ambient noise volume level decreases.
figure 49.2: AVC calibration button
Note
During the calibration, the system uses one
digital audio channel of the optical network to
distribute the calibration tone. This temporarily
decreases the number of available digital audio
channels in the system.
Note
The AVC calibration requires the Wobble tone
to be present in the tone set. If necessary, use
Activate new tone set (see section 44.4).