Patent ID: 8064543

Claim:
A channel equalizer for use in a digital television (DTV) receiving system, the channel equalizer comprising: a first transformer configured to convert input data in a digital television (DTV) signal into frequency domain data, wherein the DTV signal includes a data group comprising a first region having a plurality of segments, a second region having a plurality of segments and a third region having a plurality of segments, the second region being positioned between the first and third regions, the first and third regions including main data, RS parity data and enhanced data, the second region including enhanced data, known data sequences, signaling information, and RS parity data but no main data, wherein at least two segments in the second region have different start positions of the known data sequences, and wherein at least two of the known data sequences are spaced 16 segments apart; a channel estimator configured to estimate a channel impulse response (CIR) of the input data using at least one of the known data sequences; a second transformer configured to convert the estimated CIR into frequency domain data; a coefficient calculator configured to calculate equalization coefficients using the frequency domain CIR; a first multiplier configured to multiply the input data in the frequency domain with the equalization coefficients for channel equalization; and a third transformer configured to convert the channel-equalized data into time domain data.