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US 4,052,740 AGranted
Moire interference reducing circuit for FM video recorders
AssigneeAmpex Corporation
InventorCharles Hubert Coleman, Jr.
Life of this patent
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AssigneeAmpex Corporation
InventorCharles Hubert Coleman, Jr.
Estimating the term…
A method and apparatus for suppressing spurious interference components that arise in video recording apparatus of the type which utilize frequency modulation of the carrier signal with a video signal is disclosed. The invention suppresses an unwanted spurious interference signal component substantially to zero by generating the second harmonic of a fundamental signal in the video information modulating signal and adding the second harmonic to the fundamental modulating signal at a predetermined phase and amplitude prior to being modulated upon the carrier signal. The phase is such that the resulting signal is that which, when the second harmonic is added, heightens the upward deviating peaks and flattens the lower peaks of the fundamental modulating signal. The amplitude of the added second harmonic is such as to minimize the interference component and is varied signal in direct proportion to the square of any variation in the modulating index of the fundamental modulating signal.
A method of reducing a spurious interference component in a demodulated signal of a frequency modulated signal transmission system wherein a modulating signal having a fundamental frequency modulates a carrier signal, the spurious interference component being caused by interaction between the fundamental frequency and the carrier signal, comprising the steps of:
A method of reducing an undesirable sideband located within the demodulated output of a color videotape recording system of the type where a color video signal, having a color subcarrier, frequency modulates a carrier signal, comprising the steps of:
Frequency modulation apparatus for processing a modulating signal to reduce at least one order of spurious frequency components that can otherwise appear in the demodulated output of said apparatus and be generated by the interaction between the modulating signal and a carrier signal modulated by said modulating signal, comprising:
Apparatus for use in a color video recorder of the type wherein a color video signal frequency, having a color subcarrier, modulates a carrier signal, said apparatus being adapted to reduce at least one order spurious interference component that can otherwise appear in the demodulated color video signal during playback of a color video recording recorded on said recorder, the spurious interference component being otherwise generated by the interaction between the carrier signal and the color subcarrier, comprising:
In a frequency modulated signal transmission system wherein a carrier signal is frequency modulated by a modulating signal including a fundamental frequency signal, a method of reducing a spurious interference component which can be caused by the interaction between the fundamental frequency signal and the carrier signal and can appear in the demodulated modulating signal provided by said system, comprising the steps of:
Dependencies are inferred from the claim text.