Non linear amplitude precorrection for HDTV transmitter
AssigneeZenith Electronics Corporation
InventorFrank C. Templin
Life of this patent
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Abstract
A circuit for developing correction signals for on-line controlling a precorrection arrangement in an HDTV 8VSB digital signal transmitter. The transmitted signal is sampled, sorted, smoothed and sliced to determine the symbol amplitude levels of the transmitted multilevel symbols. The centers of the sliced clusters of sampled symbol levels are used to determine the symbol amplitude levels. Correction signals for compensating the precorrection arrangement are developed based upon the determined symbol levels and the known symbol levels.
Claims35
In connection with a transmitted signal having n signal levels, wherein n is greater than 2, a method of determining the n signal levels comprising the following steps:
- a) forming a histogram from the transmitted signal, wherein the histogram represents deviations of the received signal about the n signal levels;
- b) determining the n signal levels from the histogram.
In connection with an 8 VSB transmitted signal containing symbols, wherein each symbol corresponds to one of at least seven signal levels, a method of determining the at least seven signal levels comprising the following steps:
- a) forming a histogram from the 8 VSB transmitted signal, wherein the histogram represents deviations of the received signal about the at least seven signal levels;
- b) determining the at least seven signal levels from the histogram.
Dependencies are inferred from the claim text.