EP0256753A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for preventing the copying of a video program
Assignee: Adeia Media LLC
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Filing: 1987-08-04
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Granted: —
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Expires: 2007-08-04
Abstract
Abstract A video signal is modified so that a television receiver will still provide a normal color picture but which a video tape recorder will detect and prohibit its being recorded. A plurality of ordered pairs of pseudo-sync and positive pulses are added to the video signal vertical blanking interval following the normal sync pulse. A disabling circuit (22) in a video tape recorder (10) detects the modified signal. This detection may be by comparing the voltage differential between the pseudo-sync pulse tip and the positive pulse relative to the normal voltage differential between the sync pulse tip and the back porch of the blanking interval. Alternatively, the modified signal can be detected by identifying the pulse frequency of the signal in the blanking interval. A high frequency is indicative of the presence of the modified signal. A control signal (26) is produced by the disabling circuit (22) when the modified signal is present, and this disables a recording device (20). If no modified signal is detected, the recording device is enabled.
Inventors
- 👤 John O. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 13:26
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/00086; G11B20/00681; G11B20/00702; G11B27/00; G11B27/02; G11B27/022; G11B27/028; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/913; G11B2220/00; G11B2220/40; G11B2220/45; G11B2220/455; G11B2220/90; G11B2220/91; G11B27/024; H04N2005/91307; H04N2005/91314
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
77 words
A method for recording selected video signals having a blanking interval which includes a sync pulse, and for prohibiting the recording of modified video signals having a selected waveform added to the video signals within the blanking interval, said method comprising: receiving video signals in a video signal recording device; detecting the presence of the added selected waveform in the modified video signal; and prohibiting recording of the modified video signal by the video signal recording device.
Claim 2
Independent Claim
77 words
A method for recording selected video signals having a blanking interval which includes a sync pulse, and for prohibiting the recording of modified video signals having a selected waveform added to the video signals within the blanking interval, said method comprising: receiving video signals in a video signal recording device; detecting the presence of the added selected waveform in the modified video signal; and prohibiting recording of the modified video signal by the video signal recording device.
Claim 3
Dependent Claim
53 words
A method as claimed in Claim 1, wherein said prohibiting includes generating a control signal indicating the presence of the selected waveform in the received video signal, and preventing the recording device from recording the received video signal when the control signal indicates the presence of the selected waveform in the video signal.
Claim 4
Dependent Claim
49 words
A method as claimed in Claim 2, further comprising generating a control signal indicating the absence of the selected waveform in the video signal, and enabling the recording device to record the video signal when the control signal indicates the absence of the selected waveform in the video signal.
Claim 5
Independent Claim
27 words
A method as claimed in any preceding claim, wherein said selected waveform includes at least one selected pulse added to the video signal following the sync pulse.
Claim 6
Dependent Claim
72 words
A method as claimed in Claim 4, wherein said selected waveform includes a plurality of pulses added following the sync pulse, and said detecting includes generating a signal having a voltage proportional to the frequency of the plurality of pulses following the sync pulse, sampling the generated signal when it has a voltage proportional to the selected-pulse frequency, and holding the value of the sample for a minimum predetermined period of time.
Claim 7
Dependent Claim
119 words
A method as claimed in Claim 4, wherein said selected waveform includes a pseudo-sync pulse after the sync pulse and a positive pulse after each pseudo-sync pulse and within the blanking interval such that the amplitude differential between each pseudo-sync pulse and associated positive pulse is different to the normal amplitude differential between the sync pulse and the blanking interval following the sync pulse, and said detecting includes detecting the amplitude differential between each pseudo-sync pulse and the associated positive pulse by sampling the voltage of the video signal after each pseudo-sync pulse at a time when a corresponding positive pulse is present, and holding the value of the sample for at least a minimum predetermined period of time.
Claim 8
Dependent Claim
27 words
A method as claimed in Claim 5 or 6, wherein the predetermined period of time is at least the duration of a line of the video signal.
Claim 9
Dependent Claim
27 words
A method as claimed in Claim 5 or 6, wherein the predetermined period of time is at least the duration of a field of the video signal.
Claim 10
Dependent Claim
114 words
Tape recording apparatus for recording selected video signals having a blanking interval which includes a sync pulse, and for prohibiting the recording of modified video signals having a selected waveform added to the selected video signals within the blanking interval, the apparatus comprising: input means (18) for receiving a video signal; recording means (20) responsive to a control signal (26) and coupled to said input means for recording selected video signals on the recording medium (16); and disabling means coupled to said input means (18) and to said recording means (20), and responsive to a modified video signal, for generating the control signal for disabling said recording means from recording the modified video signal.
Claim 11
Dependent Claim
114 words
Tape recording apparatus for recording selected video signals having a blanking interval which includes a sync pulse, and for prohibiting the recording of modified video signals having a selected waveform added to the selected video signals within the blanking interval, the apparatus comprising: input means (18) for receiving a video signal; recording means (20) responsive to a control signal (26) and coupled to said input means for recording selected video signals on the recording medium (16); and disabling means coupled to said input means (18) and to said recording means (20), and responsive to a modified video signal, for generating the control signal for disabling said recording means from recording the modified video signal.
Claim 12
Dependent Claim
29 words
A tape recording apparatus as claimed in Claim 9, wherein said disabling means (22) comprise means for detecting the presence of the selected waveform in a modified video signal.
Claim 13
Dependent Claim
123 words
A tape recording apparatus as claimed in Claim 9 or 10 arranged to prohibit recording of video signals having at least one ordered pulse pair, including a pseudo-sync pulse following the sync pulse and a positive pulse following the pseudo-sync pulse, the difference in amplitude between the pseudo-sync pulse tip and the positive pulse being different to the normal amplitude difference between the sync pulse tip and the blanking interval following the sync pulse, wherein said disabling means (22) comprises means for detecting the amplitude difference between each pseudo-sync pulse tip and the associated positive pulse, and means for holding a voltage representative of the amplitude difference between each pseudo-sync pulse tip and the associated positive pulse a minimum predetermined period of time.
Claim 14
Dependent Claim
74 words
A tape recording apparatus as claimed in Claim 9 or 10 arranged to prohibit the recording of video signals having plurality of pseudo-sync pulses added after the sync pulse, said disabling means (22) comprising means for detecting the frequency of the plurality of pseudo-sync pulses, for generating a voltage representative of the frequency of the pseudo-sync pulses, and for holding the voltage representative of the pseudo-sync pulse frequency a minimum predetermined period of time.
Claim 15
Dependent Claim
59 words
A tape recording apparatus as claimed in any of Claims 9 to 12 arranged to prohibit the recording of video signals having at least one positive pulse added after the sync pulse and having an amplitude greater than the normal blanking reference level, said disabling means (22) comprising means (42) for detecting the peak amplitude of the video signal.
Claim 16
Dependent Claim
22 words
A tape recording apparatus as claimed in Claim 13, wherein said detecting means also samples the peak-detected signal during the blanking interval.
References Cited (Backward Citations)
No citation records indexed.
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