Philips TW0200, Manual

7-3.3   
 5. Fresnel zone: -  

No. of concentric ellipsoid revolutions which defines volumes in radiation pattern of 

ircular aperture and it is due to diffraction by circular aperture 

ar in cross section and concentric 

 near the path of radio beam. 

                      TR – Direct path and TAR –   

ary transmission path  

eflection of M/W energy from A.  

 in radio system

fading / Slow fading: - It is due to multipath propagation 

 of transmitted signal that have experiences due to diffraction, 

tion, delay and phase shift while traveling from the source to receiver. 

 attenuation of single signal. It refers to the time variation of received 

ement 

le antenna. 

margin or sensitivity to accommodate expected 

ality. It is margin by which Rx level may be 

ce to fall below a specific value. 

l continue to work till -80 dBm. It means fade 

   7.    X- PIC: - Cross polarization interference cancellers: -  

limited frequency spectrum  

 can cause the 

eters which is called cross 

ipath propagation, antenna 

n received 

eceive of M1 

ow let M2 channel transmit the power, measure receive power at station B of M1 

hannel again so  

PD will be difference of these two readings. 
PD: - Both received signals are decoupled by XPD of antenna at the receiving end. 

c
The first zone is circular; sub second zones are annul
with first. 
This zone concept is used to analyze interference by obstacle
                                                             
                                                                                    Second
                                                                                    by r
T                             A                         R 
 
 
 

                                                   Hilly Terrain 
 
 
    
  6. Fading: -

 It is a distortion in micro media and introduces errors

There are two types of fading: -  

1.

Slow (shadow) fading: - It is on large scale due to movements of mobile or 
obstruction within propagation environment. 

2.

Past fading/ Multipath 
by superimposition
in attenua
This is by
signal caused by changes in transmission media. It occurs with small mov
of mobile obstacle. 
Remedy: - Diversity through multip

Fade Margin: - There should be sufficient 
fading to achieve the requisite system qu
reduced without causing system performan
e.g. let Rx level -40 dBm and system wil
margin is 40 dB 

Frequency reuse technique is adopted in micro system due to 
a microwave signal is transmitted to both vertical and horizontal feeds and are coupled, in
the antenna. These two vertical and horizontal polarized signals
interference due to cross polarization, due to rain or hydrom
polarization interference the reasons are rain, hydro, mult
characteristics the cross pick use to cancel the effect of XPD of both signal i
direction  
E.g. now station A transmit power on M1 channel measure at station B on r
channel. 
N
c
X
X

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