Patent US5058159A successfully refreshed from Google Patents.
US5058159A
Expired / Lapsed
US
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Method and system for scrambling and descrambling audio information signals
Assignee: Adeia Media LLC
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Filing: 1989-06-15
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Granted: 1991-10-15
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Expires: 2009-06-15
Abstract
Abstract Audio signals are scrambled by inverting the original; frequency spectrum so that frequency portions originally lying at the lower end of the audio frequency band are shifted to the upper end while those portions originally lying near the upper end of the band are shifted to the lower end. A pilot tone of known frequency is recorded along with the frequency shifted audio signals, along with accompanying video signal portions. Upon reproduction, any variations in phase and frequency introduction by the recording or reproduction process are tracked by the pilot tone, which is used to generate the demodulation signal for restoring the original frequency content of the audio signals.
Inventors
- 👤 Ronald Quan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:20
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04K; H04K1/00; H04K1/04
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
83 words
A method of scrambling audio information signals having frequency components lying within an original frequency spectrum, said method comprising the steps of: (a) frequency shifting original time domain audio information signals to produce scrambled audio information signals; (b) generating a pilot signal of a preselected frequency; and (c) recording both the scrambled audio information signals and the pilot signal on a common recording medium so that any frequency variations introduced in the scrambled audio signals upon playback are tracked by the pilot signal.
Claim 2
Independent Claim
83 words
A method of scrambling audio information signals having frequency components lying within an original frequency spectrum, said method comprising the steps of: (a) frequency shifting original time domain audio information signals to produce scrambled audio information signals; (b) generating a pilot signal of a preselected frequency; and (c) recording both the scrambled audio information signals and the pilot signal on a common recording medium so that any frequency variations introduced in the scrambled audio signals upon playback are tracked by the pilot signal.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said step (a) of frequency shifting includes the step of varying the magnitude of the frequency shift.
Claim 4
Dependent Claim
14 words
The method of claim 2 wherein said step of varying is performed pseudo randomly.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein said step (a) of frequency shifting includes the step of inverting the frequency spectrum of the original audio information signals.
Claim 6
Dependent Claim
24 words
The method of claim 4 wherein said step of inverting includes the step of performing single side band modulation of said audio information signals.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein said preselected pilot signal has a frequency outside the frequency band of said scrambled audio information signals.
Claim 8
Dependent Claim
41 words
The method of claim 1 further including the steps of generating coded information signals relating to the manner in which the frequency shifting is performed in step (a), and associating said coded information signals to the recorded scrambled audio information signals.
Claim 9
Independent Claim
110 words
A method of descrambling audio information signals previously scrambled by frequency shifting original time domain audio information signals having frequency components lying within an original frequency spectrum and recording the frequency shifted audio information signals along with a pilot signal having a preselected frequency, said descrambling method comprising the steps of: (a) reproducing the scrambled audio information signal and the pilot signal; (b) using the pilot signal to generate a frequency restoring demodulation signal containing any frequency variations introduced by step (a); and (c) demodulating the reproduced scrambled audio information signals with the demodulation signal from step (b) to produce final audio information signals lying within the original frequency spectrum.
Claim 10
Independent Claim
110 words
A method of descrambling audio information signals previously scrambled by frequency shifting original time domain audio information signals having frequency components lying within an original frequency spectrum and recording the frequency shifted audio information signals along with a pilot signal having a preselected frequency, said descrambling method comprising the steps of: (a) reproducing the scrambled audio information signal and the pilot signal; (b) using the pilot signal to generate a frequency restoring demodulation signal containing any frequency variations introduced by step (a); and (c) demodulating the reproduced scrambled audio information signals with the demodulation signal from step (b) to produce final audio information signals lying within the original frequency spectrum.
Claim 11
Dependent Claim
26 words
The method of claim 8 wherein said step (c) of demodulating includes the step of performing single side band modulation on said scrambled audio information signals.
Claim 12
Dependent Claim
57 words
The method of claim 8 wherein said scrambled audio information signals have associated coded information signals relating to the manner in which the frequency shifting was performed; and wherein said method further includes the steps of recovering the associated coded information signals and using the associated coded information signals to select the frequency of the demodulation signal.
Claim 13
Dependent Claim
39 words
The method of claim 10 wherein said associated coded information signals include a starting frequency indication signal; and wherein said step of using includes the step of using the starting frequency indication signal to initialize the initial demodulation frequency.
Claim 14
Independent Claim
85 words
A system for scrambling audio information signals having frequency components lying within an original frequency spectrum, said system comprising: means for frequency shifting original time domain audio information signals to produce scrambled audio information signals; means for generating a pilot signal of a preselected frequency; and means for combining the scrambled audio information signal and the pilot signal prior to recording on a common recording medium so that any frequency variations introduced in the scrambled audio signals upon playback are tracked by the pilot signal.
Claim 15
Independent Claim
85 words
A system for scrambling audio information signals having frequency components lying within an original frequency spectrum, said system comprising: means for frequency shifting original time domain audio information signals to produce scrambled audio information signals; means for generating a pilot signal of a preselected frequency; and means for combining the scrambled audio information signal and the pilot signal prior to recording on a common recording medium so that any frequency variations introduced in the scrambled audio signals upon playback are tracked by the pilot signal.
Claim 16
Dependent Claim
20 words
The system of claim 12 wherein said frequency shifting means includes means for varying the magnitude of the frequency shift.
Claim 17
Dependent Claim
18 words
The system of claim 13 wherein said varying means includes means for pseudo randomly varying the frequency shift.
Claim 18
Dependent Claim
22 words
The system of claim 12 wherein said frequency shifting means includes means for inverting the frequency spectrum of the audio information signals.
Claim 19
Dependent Claim
15 words
The system of claim 15 wherein said inverting means includes a single side band modulator.
Claim 20
Dependent Claim
21 words
The system of claim 12 wherein said pilot signal has a frequency lying outside the scrambled audio information signal frequency band.
Claim 21
Dependent Claim
43 words
The system of claim 12 further including means for generating coded information signals relating to the manner in which the frequency shifting means operates and means for associating said coded information signals to the combined scrambled audio information signals and the pilot signal.
Claim 22
Independent Claim
116 words
A system for descrambling audio information signals previously scrambled by frequency shifting original time domain audio information signals having frequency components lying within an original frequency spectrum and recording the frequency shifted audio information signals along with a pilot signal having a predetermined frequency, said descrambling system comprising: means for reproducing the scrambled audio information signals and the pilot signal; means responsive to the pilot signal for generating a frequency restoring demodulation signal; and means responsive to the demodulation signal for demodulating the reproduced scrambled audio information signals to produce final audio information signals lying within the original frequency spectrum and substantially devoid of any frequency variations introduced in the scrambled audio information signals upon reproduction.
Claim 23
Independent Claim
116 words
A system for descrambling audio information signals previously scrambled by frequency shifting original time domain audio information signals having frequency components lying within an original frequency spectrum and recording the frequency shifted audio information signals along with a pilot signal having a predetermined frequency, said descrambling system comprising: means for reproducing the scrambled audio information signals and the pilot signal; means responsive to the pilot signal for generating a frequency restoring demodulation signal; and means responsive to the demodulation signal for demodulating the reproduced scrambled audio information signals to produce final audio information signals lying within the original frequency spectrum and substantially devoid of any frequency variations introduced in the scrambled audio information signals upon reproduction.
Claim 24
Dependent Claim
15 words
The system of claim 19 wherein said demodulating means includes a single side band modulator.
Claim 25
Dependent Claim
55 words
The system of claim 19 wherein said scrambled signals have associated coded information signals relating to the manner in which the frequency shifting was performed; and wherein said descrambling system further includes means responsive to the associated coded information signals for enabling the demodulation signal generating means to control the frequency of the demodulation signal.
Claim 26
Dependent Claim
35 words
The system of claim 21 wherein said associated coded information signals include a starting frequency signal; and wherein said generating means is responsive to the starting frequency signal to select the initial demodulation signal frequency.
References Cited (Backward Citations)
EP0074810A2
Cited
US4747137A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-14 | 1995-04-15 | 1995-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-14 | 1999-04-15 | 1999-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-14 | 2003-04-15 | 2003-10-15 | $7700.00 | Window Closed / Lapsed |