Koninklijke Philips Corporation N.v.

Philips Electronics North America Corporation

David Koo

Dagnachew Birru

Joseph Patrick Meehan

Gennady Turkenich

A free-running sample rate converter and a large spanning, non-linear pre-equalizer are employed before a timing recovery loop within a wireless receiver chain, while forward and feedback equalization after the timing recovery loop (at and around the input of a sync detector) is also retained. A channel identifier produces a channel estimate from the PN511 training sequence within the received wireless signals, with the pre-equalizer employing the resulting channel estimate to equalize the received signals being passed to the timing recovery loop, improving the signal quality for carrier and timing recovery and decoding to increase the probability of successful decoding while enabling the use of fast tracking forward and feedback equalizers for decoding.

Pre-equalizer structure based on PN511 sequence for terrestrial DTV reception

A novel echo cancellation reference ('ECR') training signal is inserted into the current ATSC 8 VSB data stream to achieve improved echo rejection while maintaining compatibility with the ATSC 8 VSB digital ATV standard. The novel ECR training signal is also suitable for other multipath or dispersive digital communication channels. A pre-equalization subsystem is included in the digital ATV system as a front end to the VSB receiver, and is trained with preferably the novel ECR training signal. One type of pre-equalization subsystem provides a fully ATSC compliant signal at its output, and therefore is particularly useful with standard VSB receivers. Another type of pre-equalization system provides a signal at its output which is ATSC compliant in some respects but which retains the ECR signal, and therefore is particularly useful for signal relays, analysis purposes, and other applications in which the residual channel information is important.

Method and apparatus for echo cancellation in digital ATV systems using an echo cancellation reference signal

A round off mechanism maintains a mean value of the operand while rounding twos complement binary data. Positive data values are incremented at the first discard bit prior to truncation of the discard bits, as are negative data values having a one within the most significant discard bit and at least one other discard bit. The discard bits are simply truncated for all other negative data values.

Round-off algorithm without bias for 2's complement data

A novel echo cancellation reference (&ldquo;ECR&rdquo;) training signal is inserted into the current ATSC 8 VSB data stream to achieve improved echo rejection while maintaining compatibility with the ATSC 8 VSB digital ATV standard. The novel ECR training signal is also suitable for other multipath or dispersive digital communication channels. A pre-equalization subsystem is included in the digital ATV system as a front end to the VSB receiver, and is trained with preferably the novel ECR training signal. One type of pre-equalization subsystem provides a fully ATSC compliant signal at its output, and therefore is particularly useful with standard VSB receivers. Another type of pre-equalization system provides a signal at its output which is ATSC compliant in some respects but which retains the ECR signal, and therefore is particularly useful for signal relays, analysis purposes, and other applications in which the residual channel information is important.

Method and apparatus for echo cancellation in digital communications using an echo cancellation reference signal

A method for determining and reducing or eliminating mid-range and long-rang echoes in the digital data transmission (in ATSC VSB system) is described. A portion of an ATSC VSB television signal is separated from the rest of the signal, certain values are set to zero and it is correlated with a first vector of data. The result of the correlation represents a channel model as affected by echoes within the channel, and then a second vector of data is added to it to derive correction information useful in positioning moveable filter taps to suppress the most prominent echoes.

Method for correlation directed echo cancellation and channel equalization for the digital transmission link in vestigial side band amplitude modulation

An apparatus for receiving a television signal containing a ghost cancellation reference signal, and for using the reference signal to process the television signal so as to substantially eliminate path induced distortion.

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Carmel, NY, United States of America

David Koo