SSS Siedle BFS 850-02 - Example to determine the attenuation

10
3 Conguration, conductor lengths
Example to determine the attenuation
BAA 650-...
0 dB
BVVU 650-...
1 dB
BVVU 650-...
1 dB
BVVU 650-...
1 dB
12 dB
7 m
5 m
5 m
5 m
12 dB
12 dB
25 m 11 m 4 m 4 m 12 m
Apartment 1
Apartment 2
Apartment 3
Apartment 4
Example to determine the atten-
uation with bus distributor
The system is installed using YR
cable 0.8 mm diameter. This means
that 10 m of conductor length have
an attenuation of 2 dB. Apartment 4
is decoupled using a bus audio
decoupler BAA 650-... , apartment 1
- apartment 3 are connected via bus
video distributor BVVU 650-... .
Attenuation in the camera
branch
Conductor length between the door
station and the sub-distributor 25 m.
25 m = 5 dB
Attenuation in the monitor
branch to apartment 3
Conductor length of the installation
cable. All values added, from the
bus video line rectier to the bus
telephone:
11 m + 4 m + 5 m = 20 m
20 m conductor length corresponds
to 4 dB attenuation!
Attenuation of the bus distributor
BVVU 650-... = 12 dB
Total value:
12 dB distributor + 4 dB conductor
= 16 dB
This means that apartment 3 has a
total attenuation from the camera to
the bus telephone of 16 dB + 5 dB
= 21 dB
Attenuation in the monitor
branch to apartment 1
Conductor length of the installation
cable. All values added, from the
bus video line rectier to the bus
telephone:
11 m + 4 m + 4 m + 12 m + 7 m
= 38 m
38 m of conductor material add up
to 7.6 dB
Attenuation of all bus distributors:
1 dB + 1 dB + 12 dB = 14 dB
Total value:
14 dB distributor + 7.6 dB conductor
= 21.6 dB
Apartment 1 has a total attenuation
from the camera to the bus tel-
ephone of 21.6 dB + 5 dB = 26.6 dB
The maximum value with this
example would be 26.6 dB from
the most distant video door station
to the most distant bus telephone,
the maximum admissible would be
45 dB.
With greater attenuation over 45 dB,
accessory ZBVNG 650-... can be
used to increase attenuation in the
camera branch to 45 dB and in the
monitor branch to 55 db.
On the following double page, the
precise function of the bus distrib-
utor is explained in detail.