Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1990-07-31
1993-01-05
Groody, James J.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358909, H04N 521
Patent
active
051776111
ABSTRACT:
High definition or enhanced television signals include supplementary information which is double-sideband modulated in quadrature with the picture carrier, and passed through an inverse Nyquist filter before being combined with a conventional vestigial sideband modulated main video signal. A receiver which recovers both the main video signal and the supplementary information processes the received video signal through an IF filter having a vestigial sideband frequency response characteristic. Two synchronous detectors recover in-phase and quadrature phase signal components from the filtered television signals, these recovered signals each include quadrature crosstalk distortion components from the other signal. The crosstalk from the supplementary signal into the main signal is canceled by filtering the recovered quadrature signal and adding the result to the recovered in-phase signal. This filtering also equalizes the in-phase signal by converting the quadrature distortion components in the recovered quadrature signal into reenforcing signal components in the in-phase signal. This signal recovery system is advantageously used with a ghost cancellation system.
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Gibson James J.
Jonnalagadda Krishnamurthy
Groody James J.
Hayes James B.
Herrmann Eric P.
Powell Mark R.
RCA Licensing Corporation
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