Philips TW0200 - Manual (Page 38)

Antenna diversity: - In this diversity schem microwave signals are transmitted along
st instantaneously on failure of
11
Thi
for
ove
1. B
2. Frame Synch loss when BER >10
3. CMI O/P to Mux is lost
Here Priority is 3>2>1
Process:-
- Fault in reg annel detected at receiving end.
- Faulty cha l switching control is transmitte received end to transm
end.
- Transmitted end switch control disconnect radio pilot signal from the protection
channel and transmit the I/C regular and Prot. channel is detected.
- Hitless switching for regular to protection channel takes place.
12. Free Space loss: -
It is the lo ilar antennas in free Space where there is no ground
Loss of signal strength due to absorbing, diffracting, obstructing, Refracting, Scattering
and reflecting when two Antennas are is free space without connector, Cable loss.
e
with different propagation path with the help of second antenna at receiving end to
improve received performance.
7-3.5
10. Hot stand by: -
If main equipment fails automatic switch over takes place on a stand by equipment set i.e.
a complete set of parallel equipment is switched in almo
operating equipment. This is also called a equipment diversity. It requires only one set of
frequency for frequency for a particular route. Here there is no frequency diversity so one
band of frequency is saved. In this Configuration system is 1+1 on 6+1 i.e. 1 or 6 main
channel and one is protection channel.
. Hitless switching [Error less switching]:-
s is carried out at base band stage only for fading condition and manual switching is
maintenance purpose. Protection switching is inhibited at receive side and change
r taken place when,
ER> 10
-3
ular ch
nne d from itted
ss between two sim
interference, obstruction.
Free space loss = 32.45 +20 log D+ 20 log F
Where D= Distance in Km
F= Frequency in MHz or
Free loss = 20 Log FD+92.4
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