Improved techniques for time domain equalization are disclosed. The improved techniques include (i) improved time domain equalization techniques referred to as poly-path time domain equalization techniques; (ii) improved training methods for training transmitters and/or receivers of a data transmission system; and (iii) techniques for providing time domain equalization to a transmitter side of a data transmission system. These techniques are particularly suitable for time domain equalization in multicarrier modulation systems where channel shortening provided by time domain equalization is particularly needed.