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US 2008/0075201 A1Published application
Insertion of repetitive PN sequences into DTV data fields
OwnerAllen LeRoy Limberginventor
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OwnerAllen LeRoy Limberginventor
Estimating the term…
An echo cancellation reference signal is generated within a DTV transmitter by approximating a pair of successive repetitive PN sequences with 8VSB symbols arranged in sequences that are capable of being generated by ⅔ trellis coding. The trellis coding is controlled so that the two sequences of 8VSB symbols can be linearly combined to generate a repetitive PN sequence doubled in amplitude and superposed on a constant-value pedestal. After this linear combining is performed by a comb filter in a DTV receiver, the resulting signal is convolved with the PN sequence as known a priori at the DTV receiver. This is a correlation procedure which generates the impulse response of the channel through which the DTV signal was received. The channel impulse response (CIR) provides a basis for computing the weighting coefficients of adaptive channel-equalization filtering in the DTV receiver.
A vestigial-sideband amplitude-modulation signal manifested in electromagnetic field variations wherein the modulating signal is a digital signal that uses an eight-level symbol alphabet and is superposed on a pedestal, said digital signal composed of successive frames each composed of two respective fields of symbols of said digital signal, each said field composed of a respective initial segment of 832 symbols succeeded by respective 312 consecutive further segments of 832 symbols apiece, the four initial symbols of each of said segments of 832 symbols being a prescribed data segment synchronizing signal sequence, the final 828 symbols of said 312 further segments of each said field of digital symbols being consistent with prescribed ⅔ trellis coding, said vestigial-sideband amplitude-modulation signal characterized by an improvement wherein:
Dependencies are inferred from the claim text.