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Bosch Security Systems | 2011-02
Praesideo 3.5 | Installation and User Instructions | EN54-16: 2008 en | 53
figure 1: VACIE frequency response limits without
microphone(s)
Key
1 - relative output signal level, with reference to 0 dB signal
level measured at 1 kHz (dB)
2 - 1/3 octave frequency band (Hz)
figure 2: VACIE frequency response limits with
microphone(s)
Key
1 - relative output signal level, with reference to 0 dB signal
level measured at 1 kHz (dB)
2 - 1/3 octave frequency band (Hz)
The frequency response of all Praesideo sound paths that
do not include microphones is within the specified limits of
this clause, with the following remarks for the
LBB4428/00.
The frequency response of the LBB4428/00 power
amplifier shows some interaction with the attached load
impedance. For certain load conditions this causes a
resonance peak around 10-20 kHz, just exceeding the
+1 dB limit in the frequency band between 6 and 8kHz.
The installer shall use the built-in parametric equalizer of
this amplifier to flatten the frequency response of each
channel by activating the high frequency shelving filter, with
gain setting -2 dB at a corner frequency of 6.8 kHz. This
setting is valid for all rated load conditions.
A high pass filter at 68 Hz in the equalizer section is
enabled by default to decrease the risk of loudspeaker
transformer saturation for high level low frequency signals.
The high pass filter must remain enabled.
The frequency response of all Praesideo sound paths that
include microphones is within the specified limits of this
clause.
NOTE - The frequency response limits exclude
loudspeakers.
NOTE - A bandwidth of 400 Hz to 4 kHz is sufficient to
achieve acceptable intelligibility in some acoustic
environments. However, a higher frequency limit may be
necessary to achieve acceptable intelligibility in more
difficult acoustic environments due, for example, to the
masking effect caused by reverberation and/or ambient
noise.
13.13 Message store(s) Praesideo is compliant.
Pre-recorded messages shall be stored in non-volatile
memory that retains the messages when all power sources
are removed.
The pre-recorded messages of the Praesideo system are
digitally stored on a Compact Flash card in uncompressed
format (linear PCM, 16-bit, 44.1kHz). This card retains the
messages when all power sources are removed.
NOTE - The use of tapes or magnetic or optical data disks
for the storage of emergency messages is not acceptable
at the time of drafting this European Standard (see
Annex C)
Clause / Requirement Compliance Signature
2
4,0 8,0 20
-10
0,4
-20
-15
0
1
10
-1
0,125
15
20
1
1,0
2
4,0 10
-10
0,5
-20
-15
0
5
10
-5
0,2
15
20
1
1,0
0,63
0,8
1,6
1,25