User's Manual

UHF Fibre-Fed Remote Site
User Handbook
Handbook N.-60-137601HBK Issue No:-1
Date:-18/03/2005
Page:-
20 of 38
4.2 Switched Attenuator (10-000901)
4.2.1 General Application
In many practical applications for Cell Enhancers etc., the gain in each path is found to be
excessive. Therefore, provision is made within the unit for the setting of attenuation in each
path, to reduce the gain. The attenuators are located between the first and second stage
amplifiers, (fitting the attenuators in any other position would be detrimental to the noise
and/or output power performance of the Cell Enhancer).
4.2.2 Switched Attenuators
The AFL switched attenuators are available in two different types; 0 – 30dB in 2 dB steps, or
0 – 15dB in 1 dB steps (as in this case). The attenuation is simply set using the four miniature
toggle switches on the top/side of each unit. Each switch is clearly marked with the
attenuation it provides, and the total attenuation in line is the sum of the values switched in.
They are designed to maintain an accurate 50 impedance over their operating frequency at
both input and output and have a low ‘0dB’ insertion loss, typically less than 0.3dB.