Filter circuits
First Claim
Patent Images
1. A filter circuit for eliminating noise from an input signal of known frequency content comprising:
- signal separating means receiving an input signal to be filtered including at least a first delay circuit for delaying said input signal by an amount equivalent to a period of the maximum frequency of said input signal to produce a first delay signal and a second delay circuit for delaying said first delay signal by an amount equivalent to a period of the maximum frequency of said input signal to produce a second delay signal, such that said input signal, said first delay signal, and said second delay signal represent adjacent ones of plural separated signals spaced apart from each other at predetermined different time points; and
logical operating means having at least three input terminals each being supplied with a corresponding one of said plural separated signals from said signal separating means and including means for detecting a level of said input signal at said different time points for producing a filtered output signal having a desired waveform by processing said adjacent ones of said plural level detected separated signals based on a predetermined logical formula.
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Abstract
A filter circuit has an input terminal supplied with an input signal to be filtered, a signal sampling circuit for detecting a level of the input signal at plural predetermined different points spaced apart from each other and producing plural detected signals, which includes a logical operating circuit for producing a filtered output signal of a desired waveform by processing the adjacent signals of the plural detected signals based on a predetermined logical formula.
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Citations
18 Claims
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1. A filter circuit for eliminating noise from an input signal of known frequency content comprising:
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signal separating means receiving an input signal to be filtered including at least a first delay circuit for delaying said input signal by an amount equivalent to a period of the maximum frequency of said input signal to produce a first delay signal and a second delay circuit for delaying said first delay signal by an amount equivalent to a period of the maximum frequency of said input signal to produce a second delay signal, such that said input signal, said first delay signal, and said second delay signal represent adjacent ones of plural separated signals spaced apart from each other at predetermined different time points; and logical operating means having at least three input terminals each being supplied with a corresponding one of said plural separated signals from said signal separating means and including means for detecting a level of said input signal at said different time points for producing a filtered output signal having a desired waveform by processing said adjacent ones of said plural level detected separated signals based on a predetermined logical formula. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for separating a chrominance and a luminance signal from a composite color video signal, comprising:
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filter means receiving said composite color video signal for separating the chrominance component and a high-frequency luminance component as a first signal and a low-frequency luminance component as a second signal; delay circuit means receiving said first signal and producing a plurality of time-delayed output signals therefrom in which each output signal is delayed in time relative to the next preceding signal by a predetermined time period; logical operating means receiving said plurality of time-delayed output signals for performing logical operations thereon and producing a logic output signal therefrom; signal combining means for adding a selected one of said plurality of time-delayed output signals to said logic output signal to produce said chrominance signal of said color video signal and for subtracting said logic output signal from said selected one of said time delayed output signal to produce a difference signal; and means for combining said difference signal and said low-frequency luminance component to form said luminance component of said color video signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification