Apparatus for discriminating television signal
First Claim
1. In an apparatus for discriminating a television signal for use in a pay television system in which a scrambled television signal is transmitted from a broadcasting station and specified subscribers view by restoring the received scrambled television signal, said apparatus comprising a first sync separator connected to an output of a demodulator, a second sync separator connected to said output of said demodulator through an invertor, and a television signal discriminating control circuit means coupled to said first and second sync separators for determining whether the received television signal is from one of a pay television broadcasting station and a normal television broadcasting station in accordance with output signals from said first and second sync separators and for supplying restored television signals to a television receiver, wherein the improvement comprises:
- enabling control circuit means coupled to said first and second sync separators for controlling the outputs of said first and second sync separators and for controlling the input impedance of said first sync separator; and
initializing circuit means coupled between said signal discriminating control circuit means and said enabling control circuit means for controlling said enabling control circuit means;
wherein said enabling control circuit means initially supplies an output from said first sync separator to said signal discriminating control circuit means; and
wherein, if said signal discriminating control circuit means is not satisfied with said output from said first sync separator, said enabling control circuit means supplies an output from said second sync separator to said signal discriminating circuit means, and said enabling control circuit means changes the input impedance of said first sync separator so as to place said first sync separator in a half-enabling state.
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Abstract
A television signal discriminating apparatus adapted for use with the pay television system, which apparatus, for being compatible with the normal television system, monitors the television signal of received electric wave to detect whether it is from the pay television broadcasting station or the normal one and provides the correct video signal in accordance with the mode of modulation thereof.
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Citations
2 Claims
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1. In an apparatus for discriminating a television signal for use in a pay television system in which a scrambled television signal is transmitted from a broadcasting station and specified subscribers view by restoring the received scrambled television signal, said apparatus comprising a first sync separator connected to an output of a demodulator, a second sync separator connected to said output of said demodulator through an invertor, and a television signal discriminating control circuit means coupled to said first and second sync separators for determining whether the received television signal is from one of a pay television broadcasting station and a normal television broadcasting station in accordance with output signals from said first and second sync separators and for supplying restored television signals to a television receiver, wherein the improvement comprises:
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enabling control circuit means coupled to said first and second sync separators for controlling the outputs of said first and second sync separators and for controlling the input impedance of said first sync separator; and initializing circuit means coupled between said signal discriminating control circuit means and said enabling control circuit means for controlling said enabling control circuit means; wherein said enabling control circuit means initially supplies an output from said first sync separator to said signal discriminating control circuit means; and wherein, if said signal discriminating control circuit means is not satisfied with said output from said first sync separator, said enabling control circuit means supplies an output from said second sync separator to said signal discriminating circuit means, and said enabling control circuit means changes the input impedance of said first sync separator so as to place said first sync separator in a half-enabling state. - View Dependent Claims (2)
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Specification
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- Resources
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Current AssigneeClarion Co., Ltd. (Faurecia SA)
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Original AssigneeClarion Co., Ltd. (Faurecia SA)
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InventorsOkada, Masataka
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Primary Examiner(s)Buczinski, S. C.
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Application NumberUS06/092,401Time in Patent Office642 DaysField of Search358/124, 358/120US Class Current380/221CPC Class CodesH04N 7/171 Systems operating in the am...
