Digital television receiver with equalization performed on digital intermediate-frequency signals

摘要

A digital television signal receiver in a television set or in a digital video recorder digitizes received digital television signal as converted in frequency to a final intermediate-frequency band close to baseband, then performs equalization filtering on the digitized signal before demodulating it in the digital regime to regenerate baseband symbol coding. The equalization filtering is adaptive, and weighting coefficients for this filtering are adjusted in response to portions of the regenerated baseband symbol coding. Initial adjustment of the weighting coefficients is preferably done using selected portions of the data field synchronizing signal as a ghost cancellation reference signal, in order that convergence of the weighting coefficients to desired values proceeds more rapidly. Thereafter, adjustment of the weighting coefficients is preferably done using decision-directed methods that are continuously employed on all regenerated baseband symbols, better to track changing multipath conditions should they occur.