Channel equalizer for a digital high-definition television receiver

Claim 2

The channel equalizer for a HDTV as claimed in claim 1, wherein the composite filter part includes a delayer for delaying the input signal received from outside and transmitting the delayed signal as an I signal, a digital filter for digital filtration of the input signal received from outside and transmitting the filtered signal as a Q signal, a filter group for filtering the I signal and the Q signal received from the delayer and the digital filter using the composite filter coefficients received from the composite filter coefficient renewing part respectively and transmitting the filtered signals as a real I signal, an imaginary I signal, a real Q signal, and an imaginary Q signal, a subtracter for calculating the difference of the real I signal and the imaginary Q signal received from the filter group and transmitting the calculated difference as a first output signal, and an adder for adding the imaginary I signal and the real Q signal received from the filter group and transmitting the added signal as a second output signal.

Claim 3

The channel equalizer for a HDTV as claimed in claim 2, wherein the filter group includes a first filter for producing real I signal by filtering the I signal received from the delayer according to the real composite filter coefficient received from the composite filter renewing part, a second filter for producing imaginary I signal by filtering the I signal received from the delayer according to the imaginary composite filter coefficient received from the composite filter renewing part, a third filter for producing real Q signal by filtering the Q signal received from the digital filter according to the real composite filter coefficient received from the composite filter renewing part, and a fourth filter for producing imaginary Q signal by filtering the Q signal received from the digital filter according to the imaginary composite filter coefficient received from the composite filter renewing part.

Claim 4

The channel equalizer for a HDTV as claimed in claim 1, wherein the composite filter coefficient renewing part includes a first error calculator for calculating an error of training sequence using the synchronization signal received from outside and the first output signal received from the composite filter part, a second error calculator for calculating errors using the first and the second output signals received from the composite filter part, an error selection part generating selection signal for selecting an error of training sequence while in training sequence period and errors of general data while not in training sequence period using the synchronization signal received from outside and the first output signal received from the composite filter part, and a filter coefficient renewing part for selecting either one of the error of the training sequence and errors of general data received from the first and the second error calculators according to the selection signal received from the error selection part and calculating the real composite filter coefficient and the imaginary composite filter coefficient using the selected errors and the I signal and the Q signal produced at the composite filter part.

Claim 5

The channel equalizer for a HDTV as claimed in claim 4, wherein the first error calculator includes a memory for storing predetermined training sequence signal in advance and transmitting corresponding training sequence signal according to the synchronization signal received from outside, a slicer for converting the level of the first output signal received from the composite filter part to a transmission level, and a subtracter for calculating the difference of the training sequence signal received from the memory and the first output signal having the level converted into transmission level through the slicer and transmitting the calculated difference as an error of training sequence.

Claim 6

The channel equalizer for a HDTV as claimed in claim 4, wherein the second error calculator includes a first mapper for generating an error of first output signal received from the composite filter part, a second mapper for generating error of second output signal received from the composite filter part, and a phase error calculator for calculating errors of general data based on the signals received from the first and the second mappers and the first and the second output signals received from the composite filter part.

Claim 7

The channel equalizer for a HDTV as claimed in claim 6, wherein the first mapper has PROMs.

Claim 8

The channel equalizer for a HDTV as claimed in claim 6, wherein the second mapper generates the error of the second output signal as '0' in case the second output signals received form the composite filter part are erratic.

Claim 9

The channel equalizer for a HDTV as claimed in claim 6, wherein the second mapper has PROMs.

Claim 10

The channel equalizer for a HDTV as claimed in claim 6, wherein the second mapper has a digital filter.

Claim 11

The channel equalizer for a HDTV as claimed in claim 6, wherein the second mapper has a correlation filter.

Claim 12

The channel equalizer for a HDTV as claimed in claim 4, wherein the error selection part includes a memory for storing predetermined training sequence signals in advance and transmitting corresponding training sequence signal according to the synchronization signal received from outside, a subtracter for calculating the difference of the training sequence signal received from the memory and the first output signal received from the composite filter part, an average value calculator for calculating an average value of the signals received from the subtracter, an accumulator for accumulating the average values received from the average value calculator according to the synchronization signal received from outside, and a comparator for generating a selection signal that compares the accumulated average received from the accumulator to a preset reference value and make to select the channel equalization using training sequence if the accumulated average is greater than the reference value and to select the channel equalization using general data if the accumulated average is smaller than the reference value.

Claim 13

The channel equalizer for a HDTV as claimed in claim 12, wherein the memory has PROMs.

Claim 14

The channel equalizer for a HDTV as claimed in claim 4, wherein the filter coefficient renewing part includes a first multiplexer for receiving the real error and '0' of the errors of general data applied from the second error calculator, selecting '0' while in training sequence period and selecting real error while not in training sequence period according to the selection signal received from the error selection part, and transmitting the selected signal, a second multiplexer for receiving imaginary error and '0' of the errors of general data applied from the second error calculator, selecting '0' while in training sequence period and selecting imaginary error while not in training sequence period according to the selection signal received from the error selection part, and transmitting the selected signal, a third multiplexer for receiving error of training sequence applied from the first error calculator and signal applied from the first multiplexer, selecting error of training sequence while in training sequence period and selecting the signal applied from the first multiplexer while not in training sequence period according to the synchronization signal received from outside, and transmitting the selected signal, a fourth multiplexer for receiving the signal applied from the second multiplexer and '0', selecting '0' while in training sequence period and selecting the signal applied from the second multiplexer while not in training sequence period according to the synchronization signal received from outside, and transmitting the selected signal, a multiplier for multiplying a certain constant Δ to the signals received from the third and fourth multiplexers, and a filter coefficient calculator for calculating composite filter coefficients using the I signal and the Q signal received from the composite filter part and the signal received from the multiplier.

Claim 15

The channel equalizer for a HDTV as claimed in claim 14, wherein the certain constant is set greater than '0', but smaller than '1'.

Claim 16

The channel equalizer for a HDTV as claimed in claim 15, wherein the certain constant is set greater than 2₋₁₂, but smaller than 2₋₉.