Technique for minimizing decision feedback equalizer wordlength in the presence of a DC component

An integrated circuit receiver operating on a constellation of complex symbols, each symbol represented by a number N of bits, the receiver comprising:

• an adaptive decision feedback equalizer including:
• a decision feedback filter, constructed to receive a symbol decision having a wordlength of N−1 bits, the decision feedback filter outputting a compensated symbol decision having a wordlength of N−1 bits;
• an offset generation circuit, generating a DC value corresponding to an Nth bit representation;
• and
• a summing circuit for combining the decision feedback filter output and the DC value generated by the offset generation circuit.

An integrated circuit receiver operating on a constellation of complex symbols, each symbol capable of representation by a digital word having a wordlength N of bits, the receiver comprising:

• a feedback filter, constructed to receive an input stimulus signal having a wordlength of N−1 bits, the feedback filter outputting an output signal having a wordlength of N−1 bits;
• a correction filter constructed to provide an output signal having a single bit representation, wherein the correction filter receives coefficients from the feedback filter that are processed to generate the single-bit output signal;
• and
• means for combining the feedback filter output and the correction filter output to define a signal having a value consistent with an N-bit representation.

In an integrated circuit receiver, a method for adaptively equalizing symbols expressed as a digital word, the method comprising:

• identifying a nibble component of the word, the nibble component representing a fixed offset value;
• truncating the word to a vestigal representation excluding the nibble component;
• convolving the vestigal representation with coefficient taps in a first filter;
• convolving the fixed offset value, corresponding to the excluded nibble component, with coefficient taps in a second filter, wherein the coefficient taps are received from the first filter;
• and
• summing the convolutions.