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Integer Number Equalizer

IP.com Disclosure Number: IPCOM000087375D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Desblache, A.: AUTHOR

Abstract

In an equalization process, the outputs Y(n) of the equalizer are obtained through a convolution operation: Y(n) = Sigma(k) C(k) X(n-k) (1).

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Integer Number Equalizer

In an equalization process, the outputs Y(n) of the equalizer are obtained through a convolution operation: Y(n) = Sigma(k) C(k) X(n-k) (1).

where C(k)'s are the tap coefficients and X(n)'s are data values traveling along the transversal filter.

In fixed filters, C(k)'s are known values and may be adjusted to the integer values which allow a minimum number of arithmetic operations to be required for performing the convolution (1). For instance, the multiplications involved in (1) may he performed through conventional add and shift operations controlled by the binary "1"s of C(k). In adaptive equalizers, C(k)'s are not fixed values, but a given number N of "1"'s can be used in the binary representation of C(k). For example, if N=4, only the four first "1"'s of highest weight in the binary representation of C(k) could be taken into account.

The add and shift operations for performing the multiplication of (1) may be performed by using the circuit shown in the figure. This circuit comprises a register. including bit cells A(14) through A(o) which are loaded with C(k), in parallel, through the data input lines, and two sets of gates. One set, (G(13),G(12),...G(o), controlled by advance cycle pulses, enables the scanning and reading of the register without shift. The second set, (A(14),A(13),A(- 13),...A(o)-A(o), controlled by shift control pulses, enables the reading of the binary "1"'s of C(k), starting with the highest weighted one.

With th...