Error filtering in a hybrid equalizer system

A method of compensating for distortions introduced in sample communication signals received over a transmission medium, comprising the steps of:

• pre-filtering the sampled communication signals;
• determining one of a plurality of communication states of the sampled communication signals in response to the pre-filtered communication signals;
• generating an error signal relative to the difference between the determined states of said determining step and the pre-filtered communication signals;
• identifying a characteristic spectral shape of the transmission medium and providing a filtered output of the error generated by said generating step, the filtered output having an error filter characteristic defined in accordance with the identified characteristic spectral shape of the transmission medium;
• and
• said pre-filtering step having a pre-filter characteristic defined in accordance with the filtered output of the error signal.

An apparatus for compensating for distortions introduced in sampled communication signals received over a transmission medium, comprising:

• means for pre-filtering the sampled communication signals;
• means for determining one of a plurality of communication states of the sampled communication signals in response to the pre-filtered communication signal;
• means for generating an error signal relative to the difference between the determined states of said determining means and the pre-filtered communication signal;
• means for identifying the characteristic spectral shape of the transmission system medium and providing a filtered output of the error signal generated by said generating means, the filtered output having an error filter characteristic defined in accordance with the identified characteristic spectral shape of the transmission medium;
• and
• said pre-filtering means having a pre-filtered characteristic defined in accordance with the filtered output of the error signal.