HIGH DATA RATE RECEIVER
HDR-4G+ USER’S MANUAL
Ref. DTU 100782
Is.Rev 3.5
Date: June 1, 2021
© Safran Data Systems – IMP000074 e14r1
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It cannot be duplicated or distributed without expressed written consent.
Cable equalizer filter 3.7
The purpose of the optional cable equalizer filter is to compensate for cable degradation by means of
a digital equalizer integrated to the receiver. Analog equalizers are commonly used to solve this
problem; however a digital implementation offers the following advantages:
More flexibility,
Higher performances.
The primary cause of transmission loss below 1 GHz is skin effect, which is proportional to the square
root of frequency:
Amplitude Loss
(dB)
= A * sqrt (frequency)
Figure 74: Example of Non-linearity in a RG188A/U Cable
Since this type of non-linearity is almost linear between 500 MHz and 1 GHz (above figure), it can be
well compensated by a straight line with opposite rope of the tangent.
The sampled signal is filtered before baseband transposition. By this way, a symmetrical low-pass filter
can be implemented:
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