Technique for minimizing interference in video recorder reproducer systems
First Claim
1. A system for minimal distortion transducing of an angle modulated signal with a magnetic record medium, said signal including a carrier component and sideband components, produced in accordance with a modulating signal, comprising:
- limiter means responsive to said angle modulated signal for providing an output with a further component whose frequency is related to the frequency of said carrier component and said modulating signal, inverting means coupled to the output of said limiting means, signal combining means responsive to the output of said inverting means and said angle modulated signal to provide a further output signal, and means coupled to said further output for recording said further signal on said magnetic record medium.
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Abstract
A technique is disclosed for reducing moire type interference in a signal which is recorded and recovered from a magnetic record medium. An interference component, which is of opposite sense to that predictably occurring during the record-playback process, is generated and added to the recorded information signal. Resultant coaction of the purposely generated interference component and that produced during transducing of the information signal results in an interference cancellation providing an improved output signal from the system.
18 Citations
8 Claims
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1. A system for minimal distortion transducing of an angle modulated signal with a magnetic record medium, said signal including a carrier component and sideband components, produced in accordance with a modulating signal, comprising:
- limiter means responsive to said angle modulated signal for providing an output with a further component whose frequency is related to the frequency of said carrier component and said modulating signal, inverting means coupled to the output of said limiting means, signal combining means responsive to the output of said inverting means and said angle modulated signal to provide a further output signal, and means coupled to said further output for recording said further signal on said magnetic record medium.
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2. The invention according to claim 1, wherein the output of said limiter means includes a frequency component which is a sideband of an odd harmonic of said carrier frequency component.
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3. The invention according to claim 1, wherein the frequency of said further component fI output of said limiter means is related to said carrier frequency fc and said modulating signal fm by the expression, fI 3fc-nfm, where n is an integer.
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4. The invention according to claim 1, including signal amplitude adjusting means operative in conjunction with said signal combining means to determine the magnitude of the components of said further output signal as applied to said magnetic medium.
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5. The invention according to claim 1, wherein said signal combining means includes first means for adding said angle modulated signal with the output of said inverting means, and further means for adding said angle modulated signal with the output of said first adding means.
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6. The invention according to claim 5, including means coupled to the output of said first adding means for altering the amplitude thereof as applied to said second adding means.
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7. The invention according to claim 1, wherein said signal combining means includes means for adding said angle modulated signal with a further input thereto, first signal amplitude adjusting means for applying the output of said inverting means to said adding means, and further signal adjusting means for altering the amplitude of the output of said adding means.
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8. The invention according to claim 7, wherein said first and further signal adjusting means are variable and including means for simultaneously varying the amplitude adjustment provided by said signal adjusting means.
Specification