US5432697A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Technique for controlling the symbolic dynamics of chaotic systems to generate digital communications waveforms
Assignee: United States Department of the Army
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Filing: 1993-04-23
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Granted: 1995-07-11
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Expires: 2013-04-23
Abstract
Abstract A method and apparatus for encoding information on a chaotic system by causing tiny perturbations in an accessible system control variable, or trajectory, uses the natural underlying symbolic dynamics of the system to encode the information. The system is allowed to behave chaotically even while tracking a pre-specified information-containing symbol sequence, thus maximizing the efficiency of information encoding and transmission.
Inventors
- 👤 Scott T. Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:52
CPC Classifications
H; H03; H03B; H03B29/00; G; G05; G05B; G05B5/00; G05B5/01; H04; H04K; H04K1/00; H04K1/02; H04K1/025; H04L; H04L27/00; H04L27/001
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
99 words
Apparatus for encoding information in a chaotic oscillation, wherein small variations in a control parameter of an oscillator causes changes in the oscillation without changing the chaotic behaviour of the oscillation and wherein iteration of variables of the oscillation forms an attractor, comprising: means for generating a map of phase space trajectories of the variables of the oscillation along a section of the attractor; means for designating windows along said section and assigning symbols to said windows; and means for varying said control parameter of said oscillation to cause said trajectories to pass through selected ones of said windows.
Claim 2
Dependent Claim
99 words
Apparatus for encoding information in a chaotic oscillation, wherein small variations in a control parameter of an oscillator causes changes in the oscillation without changing the chaotic behaviour of the oscillation and wherein iteration of variables of the oscillation forms an attractor, comprising: means for generating a map of phase space trajectories of the variables of the oscillation along a section of the attractor; means for designating windows along said section and assigning symbols to said windows; and means for varying said control parameter of said oscillation to cause said trajectories to pass through selected ones of said windows.
Claim 3
Dependent Claim
33 words
Apparatus as claimed in claim 1, wherein said oscillation is a Lorenz oscillator in which the three Lorenz phase variables are represented by x, y and z voltage signals generated by the oscillator.
Claim 4
Dependent Claim
20 words
Apparatus as claimed in claim 2, wherein said map generating means comprises a comparator circuit for generating a Poincare Surface-of-Section.
Claim 5
Dependent Claim
36 words
Apparatus as claimed in claim 3, wherein said control parameter varying means comprises an analog to digital converter, and digital computer means for generating a correction to the control parameter based on an input code sequence.
Claim 6
Dependent Claim
30 words
Apparatus as claimed in claim 1, wherein said map generating means comprises a threshold detector and an analog-to-digital converter for registering data representing intersections of said trajectories with said section.
Claim 7
Dependent Claim
43 words
Apparatus as claimed in claim 5, further comprising digital computer means for calculated target data for one of said variables and wherein said control parameter varying means comprises means for comparing said target data with said data generated by said map generating means.
Claim 8
Dependent Claim
22 words
Apparatus as claimed in claim 5, wherein a Poincare Surface-of-Section of the attractor generated by the Chua's circuit includes binary symbol windows.
Claim 9
Dependent Claim
41 words
Apparatus as claimed in claim 1, comprising: a threshold logic circuit for causing an analog-to-digital converter to sample an x variable output by the oscillator based on a level of y(t) which corresponds to a surface of section through the attractor.
Claim 10
Dependent Claim
53 words
Apparatus as claimed in claim 8, further comprising a second A/D converter, computer means for generating a target trajectory based on input digitized trajectory data; and wherein said control parameter varying means comprises means for generating a control signal by comparing a difference between the sampled X variable and a desired X variable.
Claim 11
Dependent Claim
22 words
Apparatus as claimed in claim 9, wherein said difference means is a look-up table with (high byte, low byte)=(x bits, x target).
Claim 12
Dependent Claim
20 words
Apparatus as claimed in claim 9, wherein difference determining means comprises a subtract and multiply circuit in a digital-to-analog converter.
Claim 13
Dependent Claim
15 words
Apparatus as claimed in claim 1, wherein said oscillation is generated by a Chua's circuit.
Claim 14
Dependent Claim
25 words
Apparatus as claimed in claim 1, wherein said control parameter varying means is an amplifier having an output proportional to a gain of the amplifier.
Claim 15
Independent Claim
107 words
A method for encoding information in a chaotic oscillation, small variations in a control parameter of the oscillation causing changes in divergence of the oscillation about at least one focus without changing the chaotic behavior of the oscillation such that iteration of variables of the oscillation form an attractor, comprising the steps of: (a) generating a map of sampled phase space trajectories of the variables of the oscillation along a section of the attractor; (b) designating windows along said section and assigning symbols to said windows; and (c) varying said control parameter of said oscillator to cause said trajectories to pass through selected ones of said windows.
Claim 16
Independent Claim
107 words
A method for encoding information in a chaotic oscillation, small variations in a control parameter of the oscillation causing changes in divergence of the oscillation about at least one focus without changing the chaotic behavior of the oscillation such that iteration of variables of the oscillation form an attractor, comprising the steps of: (a) generating a map of sampled phase space trajectories of the variables of the oscillation along a section of the attractor; (b) designating windows along said section and assigning symbols to said windows; and (c) varying said control parameter of said oscillator to cause said trajectories to pass through selected ones of said windows.
Claim 17
Dependent Claim
48 words
A method as claimed in claim 14, wherein step (c) comprises the steps of generating a Poincare Surface-of-Section, iterating a value of a variable along the Poincare Surface-of-Section to plot a predicted trajectory, and varying the control parameter to cause the sampled trajectory to equal the predicted trajectory.
References Cited (Backward Citations)
US5007087A
Cited
US5245660A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-07-10 | 1999-01-09 | 1999-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-10 | 2003-01-09 | 2003-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-10 | 2007-01-09 | 2007-07-11 | $7700.00 | Window Closed / Lapsed |