US5157725A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for preventing external detection of signal information
Assignee: Cominvest Res AB
•
Filing: 1990-01-24
•
Granted: 1992-10-20
•
Expires: 2010-01-24
Abstract
Abstract In a method and an apparatus for preventing external detection of the signal information in video signals occurring in, and being emitted from, video signal circuits in a display unit (A, A'), or a similar unit, and comprising substantially consecutive frame or field signals, each consisting of substantially consecutive line signals, a phantom signal in the form of at least one pseudo-random bit signal sequence with properties similar to those of the video signals is emitted in addition to the video signals. A generator (C) for generating the phantom signal is connected to an external power supply line (F) to the unit (A, A') containing the video signal circuits, for output of the phantom signal on this line. By means of a control unit, the bit frequencies of the pseudo-random bit signal sequence/sequences are varied. Furthermore, the pseudo-random bit signal sequence/sequences are formed of a number of part signal sequences wtih a duration varying from one frame or field period to another.
Inventors
- 👤 Per Lindholm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:26
CPC Classifications
H; H04; H04K; H04K3/00; H04K3/40; H04K3/42; H04K3/80; H04K3/82; H04K3/825; H04K2203/00; H04K2203/10; H04K2203/14; H04K2203/30; H04K2203/32
Claims Analysis
Total Claims: 59
Claim 1
Independent Claim
100 words
A method for preventing external detection of signal information in video signals comprising steps of: a) emitting video signals containing a bit signal sequence from a video circuit; b) generating a phantom signal with at least one pseudo-random bit signal sequence and having properties similar to the bit signal sequence of the video signals emitted from the video circuit; c) varying bit frequencies of the pseudo-random bit signal sequence; d) emitting the phantom signal in addition to the video signals via electromagnetic waves; and e) supplying the phantom signal to an external power supply line connected to the video circuit.
Claim 2
Independent Claim
100 words
A method for preventing external detection of signal information in video signals comprising steps of: a) emitting video signals containing a bit signal sequence from a video circuit; b) generating a phantom signal with at least one pseudo-random bit signal sequence and having properties similar to the bit signal sequence of the video signals emitted from the video circuit; c) varying bit frequencies of the pseudo-random bit signal sequence; d) emitting the phantom signal in addition to the video signals via electromagnetic waves; and e) supplying the phantom signal to an external power supply line connected to the video circuit.
Claim 3
Dependent Claim
32 words
A method as in claim 1, wherein the pseudo-random bit signal sequence has bit frequencies different from, but of the same order of magnitude as a pixel frequency of the video signal.
Claim 4
Dependent Claim
25 words
A method as in claim 2, wherein the bit frequencies are varied at substantially the same magnitude as a line frequency of the video signal.
Claim 5
Dependent Claim
72 words
A method as in claim 3, wherein the pseudo-random bit signal sequence is given a duration corresponding to a frame or field period time of the video signals, and an ensemble average value differing from zero, the pseudo-random bit signal sequence being formed of a number of partial pseudo-random bit signal sequences, characterized in that the duration of the partial pseudo-random bit signal sequences are varied within each frame or field period.
Claim 6
Dependent Claim
33 words
A method as in claim 4, wherein the pseudo-random bit signal sequence includes a number of partial pseudo-random bit signal sequences with a duration varying from one frame or field period to another.
Claim 7
Dependent Claim
25 words
A method as in claim 5, further comprising the step of: combining a plurality of pseudo-random bit signal sequences before either step d or e.
Claim 8
Dependent Claim
31 words
A method as in claim 1, wherein the pseudo-random unit signal sequence has bit frequencies which are varied at substantially the same magnitude as a line frequency of the video signal.
Claim 9
Dependent Claim
73 words
A method as in claim 7, wherein the pseudo-random bit signal sequence is given a duration corresponding to a frame or field period time of the video signals, and an ensemble average value differing from zero, the pseudo-random bit signal sequence being formed of a number of pseudo-random bit signal partial signal sequences, characterized in that the duration of the partial pseudo-random bit signal sequences are varied within each frame or field period.
Claim 10
Dependent Claim
35 words
A method as in claim 8, wherein the pseudo-random bit signal sequence is formed of a number of partial pseudo-random bit signal sequences with a duration varying from one frame or field period to another.
Claim 11
Dependent Claim
25 words
A method as in claim 9, further comprising the step of: combining a plurality of pseudo-random bit signal sequences before either step d or e.
Claim 12
Dependent Claim
70 words
A method as in claim 1, wherein the pseudo-random bit signal sequence is given a duration corresponding to a frame or field period time of the video signals, and an ensemble average value differing from zero, the pseudo-random bit signal sequence being formed of a number of partial signal pseudo-random bit signal sequences, characterized in that the duration of the partial sequences are varied within each frame or field period.
Claim 13
Dependent Claim
33 words
A method as in claim 11, wherein the pseudo-random bit signal sequence includes a number of partial pseudo-random bit signal sequences with a duration varying from one frame or field period to another.
Claim 14
Dependent Claim
25 words
A method as in claim 12, further comprising the step of: combining a plurality of pseudo-random bit signal sequences before either step d or e.
Claim 15
Dependent Claim
33 words
A method as in claim 1, wherein the pseudo-random bit signal sequence includes a number of partial pseudo-random bit signal sequences with a duration varying from one frame or field period to another.
Claim 16
Dependent Claim
25 words
A method as in claim 14, further comprising the step of: combining a plurality of pseudo-random bit signal sequences before either step d or e.
Claim 17
Dependent Claim
25 words
A method as in claim 1, further comprising the step of: combining a plurality of pseudo-random bit signal sequences before either step d or e.
Claim 18
Independent Claim
110 words
An apparatus for preventing external detection of signal information comprising: a video signal circuit generating video signals containing signal information and connected to an external power supply line; a generating means for generating a phantom signal with at least one pseudo-random bit signal sequence and having properties similar to the video signals; a controlling means for controlling variations in a bit frequency of the pseudo-random bit signal sequence coupled to the means for generating a phantom signal; a first emitting means for emitting electromagnetic waves corresponding to the phantom signal; and a second emitting means for emitting electrical signals on the external power supply line corresponding to the phantom signal.
Claim 19
Independent Claim
110 words
An apparatus for preventing external detection of signal information comprising: a video signal circuit generating video signals containing signal information and connected to an external power supply line; a generating means for generating a phantom signal with at least one pseudo-random bit signal sequence and having properties similar to the video signals; a controlling means for controlling variations in a bit frequency of the pseudo-random bit signal sequence coupled to the means for generating a phantom signal; a first emitting means for emitting electromagnetic waves corresponding to the phantom signal; and a second emitting means for emitting electrical signals on the external power supply line corresponding to the phantom signal.
Claim 20
Dependent Claim
14 words
An apparatus as in claim 17, wherein the controlling means is a frequency modulator.
Claim 21
Dependent Claim
44 words
An apparatus as in claim 18, wherein the generating means further comprises: a plurality of basis generating means for generating pseudo-random bit signal sequences, each generating its own pseudo-random bit signal sequences with a duration varying from one frame or field period to another.
Claim 22
Dependent Claim
23 words
An apparatus as in claim 19, wherein the generating means further comprises: a maximum recurrence length shift register with an adjustable maximum length.
Claim 23
Dependent Claim
63 words
An apparatus as in claim 20, wherein the first emitting means further comprises: a first serial with a broadening fin outwardly projecting from one side of a ground plane and having surfaces perpendicular to one another and to the ground plane; and a dipole aerial arranged circularly around the broadening fin of the first aerial in a plane parallel to the ground plane.
Claim 24
Dependent Claim
24 words
An apparatus as in claim 21, wherein the generating means is coupled to a conductor for conducting video signals to a video display unit.
Claim 25
Dependent Claim
43 words
An apparatus as in claim 22, wherein the controlling means further comprises: a varying means for varying the bit frequency of the pseudo-random bit signal sequence, wherein the bit frequency is at least substantially equal to a line frequency of the video signals.
Claim 26
Dependent Claim
35 words
An apparatus as in claim 23, wherein the pseudo-random bit signal sequence has one or more bit frequencies different from, but of the same order of magnitude as a pixel frequency of the video signal.
Claim 27
Dependent Claim
31 words
An apparatus as in claim 24, further comprising: a combining circuit for combining the plurality of pseudo-random bit signal sequences from the plurality of basis generating means into the phantom signal.
Claim 28
Dependent Claim
16 words
An apparatus as in claim 25, wherein the apparatus is part of a video display unit.
Claim 29
Dependent Claim
19 words
An apparatus as in claim 25, wherein the apparatus is a separate unit connectible to a video display unit.
Claim 30
Dependent Claim
44 words
An apparatus as in claim 17, wherein the generating means further comprises: a plurality of basis generating means for generating pseudo-random bit signal sequences, each generating its own pseudo-random bit signal sequences with a duration varying from one frame or field period to another.
Claim 31
Dependent Claim
23 words
An apparatus as in claim 28, wherein the generating means further comprises: a maximum recurrence length shift register with an adjustable maximum length.
Claim 32
Dependent Claim
63 words
An apparatus as in claim 29, wherein the first emitting means further comprises: a first aerial with a broadening fin outwardly projecting from one side of a ground plane and having surfaces perpendicular to one another and to the ground plane; and a dipole aerial arranged circularly around the broadening fin of the first aerial in a plane parallel to the ground plane.
Claim 33
Dependent Claim
24 words
An apparatus as in claim 30, wherein the generating means is coupled to a conductor for conducting video signals to a video display unit.
Claim 34
Dependent Claim
43 words
An apparatus as in claim 31, wherein the controlling means further comprises: a varying means for varying the bit frequency of the pseudo-random bit signal sequence, wherein the bit frequency is at least substantially equal to a line frequency of the video signals.
Claim 35
Dependent Claim
35 words
An apparatus as in claim 32, wherein the pseudo-random bit signal sequence has one or more bit frequencies different from, but of the same order of magnitude as a pixel frequency of the video signal.
Claim 36
Dependent Claim
31 words
An apparatus as in claim 33, further comprising: a combining circuit for combining the plurality of pseudo-random bit signal sequences from the plurality of basis generating means into the phantom signal.
Claim 37
Dependent Claim
16 words
An apparatus as in claim 34, wherein the apparatus is part of a video display unit.
Claim 38
Dependent Claim
19 words
An apparatus as in claim 34, wherein the apparatus is a separate unit connectible to a video display unit.
Claim 39
Dependent Claim
23 words
An apparatus as in claim 17, wherein the generating means further comprises: a maximum recurrence length shift register with an adjustable maximum length.
Claim 40
Dependent Claim
63 words
An apparatus as in claim 37, wherein the first emitting means further comprises: a first aerial with a broadening fin outwardly projecting from one side of a ground plane and having surface perpendicular to one another and to the ground plane; and a dipole aerial arranged circularly around the broadening fin of the first aerial in a plane parallel to the ground plane.
Claim 41
Dependent Claim
24 words
An apparatus as in claim 38, wherein the generating means is coupled to a conductor for conducting video signals to a video display unit.
Claim 42
Dependent Claim
43 words
An apparatus as in claim 39, wherein the controlling means further comprises: a varying means for varying the bit frequency of the pseudo-random bit signal sequence, wherein the bit frequency is at least substantially equal to a line frequency of the video signals.
Claim 43
Dependent Claim
35 words
An apparatus as in claim 40, wherein the pseudo-random bit signal sequence has one or more bit frequencies different from, but of the same order of magnitude as a pixel frequency of the video signal.
Claim 44
Dependent Claim
31 words
An apparatus as in claim 41, further comprising: a combining circuit for combining the plurality of pseudo-random bit signal sequences from the plurality of basis generating means into the phantom signal.
Claim 45
Dependent Claim
16 words
An apparatus as in claim 42, wherein the apparatus is part of a video display unit.
Claim 46
Dependent Claim
19 words
An apparatus as in claim 42, wherein the apparatus is a separate unit connectible to a video display unit.
Claim 47
Dependent Claim
63 words
An apparatus as in claim 17, wherein the first emitting means further comprises: a first aerial with a broadening fin outwardly projecting from one side of a ground plane and having surfaces perpendicular to one another and to the ground plane; and a dipole aerial arranged circularly around the broadening fin of the first aerial in a plane parallel to the ground plane.
Claim 48
Dependent Claim
24 words
An apparatus as in claim 45, wherein the generating means is coupled to a conductor for conducting video signals to a video display unit.
Claim 49
Dependent Claim
43 words
An apparatus as in claim 46, wherein the controlling means further comprises: a varying means for varying the bit frequency of the pseudo-random bit signal sequence, wherein the bit frequency is at least substantially equal to a line frequency of the video signals.
Claim 50
Dependent Claim
35 words
An apparatus as in claim 47, wherein the pseudo-random bit signal sequence has one or more bit frequencies different from but, of the same order of magnitude as a pixel frequency of the video signal.
Claim 51
Dependent Claim
31 words
An apparatus as in claim 48, further comprising: a combining circuit for combining the plurality of pseudo-random bit signal sequences from the plurality of basis generating means into the phantom signal.
Claim 52
Dependent Claim
16 words
An apparatus as in claim 49, wherein the apparatus is part of a video display unit.
Claim 53
Dependent Claim
19 words
An apparatus as in claim 49, wherein the apparatus is a separate unit connectible to a video display unit.
Claim 54
Dependent Claim
24 words
An apparatus as in claim 17, wherein the generating means is coupled to a conductor for conducting video signals to a video display unit.
Claim 55
Dependent Claim
43 words
An apparatus as in claim 52, wherein the controlling means further comprises: a varying means for varying the bit frequency of the pseudo-random bit signal sequence, wherein the bit frequency is at least substantially equal to a line frequency of the video signals.
Claim 56
Dependent Claim
35 words
An apparatus as in claim 53, wherein the pseudo-random bit signal sequence has one or more bit frequencies different from but, of the same order of magnitude as a pixel frequency of the video signal.
Claim 57
Dependent Claim
31 words
An apparatus as in claim 54, further comprising: a combining circuit for combining the plurality of pseudo-random bit signal sequences from the plurality of basis generating means into the phantom signal.
Claim 58
Dependent Claim
16 words
An apparatus as in claim 55, wherein the apparatus is part of a video display unit.
Claim 59
Dependent Claim
19 words
An apparatus as in claim 55, wherein the apparatus is a separate unit connectible to a video display unit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-10-20 | 1996-04-20 | 1996-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-20 | 2000-04-20 | 2000-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-20 | 2004-04-20 | 2004-10-20 | $7700.00 | Window Closed / Lapsed |