Data slice circuit
First Claim
1. A data slice circuit comprising:
- comparison means for issuing a result of comparison of an arbitrary one period of a data signal with a first reference voltage;
product means for producing a product of an output of said comparison means and a signal having a frequency of at least two times a frequency of said data signal;
bit storage means for storing an output of said product means as a bit train;
duty-factor check means for checking a duty-factor of said data signal of said arbitrary one period by checking said bit train stored in said bit storage means in compliance with a predetermined rule; and
reference voltage variation means for varying said first reference voltage in accordance with an output of said duty-factor check means and for providing said first reference voltage to said comparison means.
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Accused Products
Abstract
A data slice circuit is provided for slicing the caption data or the likes included in a television signal at an optimum voltage. A product between a clock-run signal sliced by a comparator at a tentative reference voltage and a clock signal which is 16 times the clock-run signal is stored in a shift register as 16 bit information, and out of them, only the 8 bits around its center are taken in a duty-factor check block, thereby judging the suitability of the slice level. Based on the result obtained, the value of the counter is increased or decreased, and it is taken as a renewed reference voltage through a pulse width conversion circuit and an integration circuit. Also with data sliced by a renewed reference voltage, the check is executed similarly, and a slicing action at an optimum level is achieved.
10 Citations
5 Claims
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1. A data slice circuit comprising:
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comparison means for issuing a result of comparison of an arbitrary one period of a data signal with a first reference voltage; product means for producing a product of an output of said comparison means and a signal having a frequency of at least two times a frequency of said data signal; bit storage means for storing an output of said product means as a bit train; duty-factor check means for checking a duty-factor of said data signal of said arbitrary one period by checking said bit train stored in said bit storage means in compliance with a predetermined rule; and reference voltage variation means for varying said first reference voltage in accordance with an output of said duty-factor check means and for providing said first reference voltage to said comparison means.
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2. A data slice circuit comprising:
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reference voltage generating means for generating a reference voltage; comparison means for comparing said reference voltage with a data signal having a first frequency; sampling means for sampling an output of said comparison means at a second frequency, said second frequency being greater than "n" times said first frequency, "n" being greater than two; sampling start means for starting said sampling means when said output of said comparison means changes; memory means for storing a result of said sampling means as a series of binary data; duty-factor check means for detecting a duty factor of said data signal on a basis of said series of binary data; a counter for counting at said second frequency when said output of said comparison means changes, and for outputting an overflow signal when a count value of said counter becomes equal to "n", said overflow signal signalling said duty-factor check means to detect said duty factor; sampling stop means for stopping said sampling means according to said overflow signal; and reference voltage variation means for increasing said reference voltage in a first case that said binary data corresponding to an amount that said data signal is higher than said reference voltage is more than a predetermined upper limit value, and for decreasing said reference voltage in a second case that said binary data corresponding to an amount that said data signal is lower than said reference voltage is less than a predetermined lower limit value in said series of binary data, according to said duty factor. - View Dependent Claims (4)
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3. A data slice circuit comprising:
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reference voltage generating means for generating a reference voltage; comparison means for comparing said reference voltage and a data signal having a first frequency; sampling means for sampling an output of said comparison means at a rate having a second frequency of "m", "m" being greater than four times said first frequency; sampling start means for starting said sampling means when said output of said comparison means changes; memory means for storing a result of said sampling means as a series of binary data; a counter for counting an output of said sampling means when said output of said comparison means changes, and for outputting an overflow signal when a count value of said counter becomes equal to "m"; sampling stop means for stopping said sampling means according to said overflow signal; and reference voltage variation means for increasing said reference voltage in a first case that said binary data corresponding to an amount that said data signal is higher than said reference voltage is more than a predetermined upper limit value, and for decreasing said reference voltage in a second case that said binary data corresponding to an amount that said data signal is lower than said reference voltage is less than a predetermined lower limit value in said series of binary data, according to data extracted from a part of said stored binary data which is included in a substantially same time period before and after a center of one sampling period of said sampling means in said series of binary data stored in said memory means. - View Dependent Claims (5)
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Specification