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Adaptive Equalization That is Dependent On the Actual Received Signal Characteristics

IP.com Disclosure Number: IPCOM000102901D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Cutshaw, R: AUTHOR [+3]

Abstract

Typically switchable equalizers consist of independent non-interacting parallel filters with solid-state switches to switch between the various filter stages and the output. The approach shown here is different in that it can conserve components, board space and hence minimize product cost.

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Adaptive Equalization That is Dependent On the Actual Received Signal Characteristics

      Typically switchable equalizers consist of independent
non-interacting parallel filters with solid-state switches to switch
between the various filter stages and the output. The approach shown
here is different in that it can conserve components, board space and
hence minimize product cost.

      In the sole figure, the first of the two serial equalizers
produces an output O1(S) which itself is of value as an output;
hence, it is available at the selector switch. However, it also is
fed to the input of the buffer amplifier A(S).  The output function
for the first equalizer F1(S) is given by:
O1(s) = F1(S)I(S)
where:  F1(S) = transfer function of the first equalizer
 I(S) = input signal
The output of the buffer amplifier feeds the second equalizer F2(S).
Hence, its output is a function of the output of the first equalizer
and is given by:
O2(S) = F2(S)A(S)O1(S) = F2(S)A(S)F1(S)I(S) where:  F2(S) = transfer
function of the second equalizer
         A(S)  = transfer function of the amplifier

      The advantage of this approach is that the amplifier and second
equalizer modify the output of the first equalizer, taking advantage
of processing done by the first equalizer.  Clearly, this approach
can be extended to three or more sequential equalizer sections.

      Disclosed anonymously.